CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Protactinium - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"5be94823-dcf9-41fd-88a8-b630c07f38b4","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Protactinium","wgTitle":"Protactinium","wgCurRevisionId":1274596214,"wgRevisionId":1274596214,"wgArticleId":23322,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Webarchive template wayback links","Use dmy dates from February 2021","Articles with short description","Short description is different from Wikidata","Articles containing Greek-language text","Commons link is on Wikidata","Good articles","Protactinium","Chemical elements","Chemical elements with body-centered tetragonal structure","Actinides","Chemical elements predicted by Dmitri Mendeleev"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext", "wgRelevantPageName":"Protactinium","wgRelevantArticleId":23322,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":50000,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q1109","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"], "GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","ext.math.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher", "ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.math.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.15"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/1200px-Protactinium_%28Element_-_91%29_2.jpg"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="963"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/800px-Protactinium_%28Element_-_91%29_2.jpg"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="642"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/640px-Protactinium_%28Element_-_91%29_2.jpg"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="513"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Protactinium - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Protactinium"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Protactinium&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Protactinium"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Protactinium rootpage-Protactinium skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Main menu </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z">Main page</a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia">Contents</a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events">Current events</a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x">Random article</a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works">About Wikipedia</a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia">Contact us</a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia">Help</a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia">Learn to edit</a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors">Community portal</a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r">Recent changes</a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia">Upload file</a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"> Search </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Appearance </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class="">Donate</a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Protactinium" title="You are encouraged to create an account and log in; however, it is not mandatory" class="">Create account</a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Protactinium" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class="">Log in</a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Personal tools </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en">Donate</a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Protactinium" title="You are encouraged to create an account and log in; however, it is not mandatory"> Create account</a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Protactinium" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"> Log in</a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing">learn more</a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y">Contributions</a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n">Talk</a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> 1 History </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Isotopes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Isotopes"> <div class="vector-toc-text"> 2 Isotopes </div> </a> <button aria-controls="toc-Isotopes-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Isotopes subsection </button> <ul id="toc-Isotopes-sublist" class="vector-toc-list"> <li id="toc-Nuclear_fission" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Nuclear_fission"> <div class="vector-toc-text"> 2.1 Nuclear fission </div> </a> <ul id="toc-Nuclear_fission-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Occurrence" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Occurrence"> <div class="vector-toc-text"> 3 Occurrence </div> </a> <button aria-controls="toc-Occurrence-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Occurrence subsection </button> <ul id="toc-Occurrence-sublist" class="vector-toc-list"> <li id="toc-In_nuclear_reactors" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#In_nuclear_reactors"> <div class="vector-toc-text"> 3.1 In nuclear reactors </div> </a> <ul id="toc-In_nuclear_reactors-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Preparation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Preparation"> <div class="vector-toc-text"> 4 Preparation </div> </a> <ul id="toc-Preparation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Properties" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Properties"> <div class="vector-toc-text"> 5 Properties </div> </a> <ul id="toc-Properties-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Chemical_compounds" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Chemical_compounds"> <div class="vector-toc-text"> 6 Chemical compounds </div> </a> <button aria-controls="toc-Chemical_compounds-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Chemical compounds subsection </button> <ul id="toc-Chemical_compounds-sublist" class="vector-toc-list"> <li id="toc-Oxides_and_oxygen-containing_salts" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Oxides_and_oxygen-containing_salts"> <div class="vector-toc-text"> 6.1 Oxides and oxygen-containing salts </div> </a> <ul id="toc-Oxides_and_oxygen-containing_salts-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Halides" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Halides"> <div class="vector-toc-text"> 6.2 Halides </div> </a> <ul id="toc-Halides-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_inorganic_compounds" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_inorganic_compounds"> <div class="vector-toc-text"> 6.3 Other inorganic compounds </div> </a> <ul id="toc-Other_inorganic_compounds-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Organometallic_compounds" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Organometallic_compounds"> <div class="vector-toc-text"> 6.4 Organometallic compounds </div> </a> <ul id="toc-Organometallic_compounds-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Applications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Applications"> <div class="vector-toc-text"> 7 Applications </div> </a> <ul id="toc-Applications-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Precautions" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Precautions"> <div class="vector-toc-text"> 8 Precautions </div> </a> <ul id="toc-Precautions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 9 See also </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 10 Notes </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 11 References </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bibliography" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Bibliography"> <div class="vector-toc-text"> 12 Bibliography </div> </a> <ul id="toc-Bibliography-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 13 External links </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Protactinium</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 134 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-134" aria-hidden="true" > 134 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Afrikaans" lang="af" hreflang="af" data-title="Protaktinium" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target">Afrikaans</a></li><li class="interlanguage-link interwiki-am mw-list-item"><a href="https://am.wikipedia.org/wiki/%E1%8D%95%E1%88%AE%E1%89%B3%E1%8A%AD%E1%89%B2%E1%8A%92%E1%8B%A8%E1%88%9D" title="ፕሮታክቲኒየም – Amharic" lang="am" hreflang="am" data-title="ፕሮታክቲኒየም" data-language-autonym="አማርኛ" data-language-local-name="Amharic" class="interlanguage-link-target">አማርኛ</a></li><li class="interlanguage-link interwiki-anp mw-list-item"><a href="https://anp.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%88%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A5%80%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोटैक्टीनियम – Angika" lang="anp" hreflang="anp" data-title="प्रोटैक्टीनियम" data-language-autonym="अंगिका" data-language-local-name="Angika" class="interlanguage-link-target">अंगिका</a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A8%D8%B1%D9%88%D8%AA%D9%83%D8%AA%D9%8A%D9%86%D9%8A%D9%88%D9%85" title="بروتكتينيوم – Arabic" lang="ar" hreflang="ar" data-title="بروتكتينيوم" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Protoactinio" title="Protoactinio – Aragonese" lang="an" hreflang="an" data-title="Protoactinio" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target">Aragonés</a></li><li class="interlanguage-link interwiki-roa-rup mw-list-item"><a href="https://roa-rup.wikipedia.org/wiki/Protactiniu" title="Protactiniu – Aromanian" lang="rup" hreflang="rup" data-title="Protactiniu" data-language-autonym="Armãneashti" data-language-local-name="Aromanian" class="interlanguage-link-target">Armãneashti</a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Protactiniu" title="Protactiniu – Asturian" lang="ast" hreflang="ast" data-title="Protactiniu" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target">Asturianu</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Azerbaijani" lang="az" hreflang="az" data-title="Protaktinium" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target">Azərbaycanca</a></li><li class="interlanguage-link interwiki-ban mw-list-item"><a href="https://ban.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Balinese" lang="ban" hreflang="ban" data-title="Protaktinium" data-language-autonym="Basa Bali" data-language-local-name="Balinese" class="interlanguage-link-target">Basa Bali</a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%AA%E0%A7%8D%E0%A6%B0%E0%A7%8B%E0%A6%9F%E0%A7%87%E0%A6%95%E0%A7%8D%E0%A6%9F%E0%A6%BF%E0%A6%A8%E0%A6%BF%E0%A6%AF%E0%A6%BC%E0%A6%BE%E0%A6%AE" title="প্রোটেক্টিনিয়াম – Bangla" lang="bn" hreflang="bn" data-title="প্রোটেক্টিনিয়াম" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target">বাংলা</a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Protactinium" title="Protactinium – Minnan" lang="nan" hreflang="nan" data-title="Protactinium" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target">閩南語 / Bân-lâm-gú</a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%9F%D1%80%D0%B0%D1%82%D0%B0%D0%BA%D1%82%D1%8B%D0%BD%D1%96%D0%B9" title="Пратактыній – Belarusian" lang="be" hreflang="be" data-title="Пратактыній" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%9F%D1%80%D0%B0%D1%82%D0%B0%D0%BA%D1%82%D1%8B%D0%BD" title="Пратактын – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Пратактын" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target">Беларуская (тарашкевіца)</a></li><li class="interlanguage-link interwiki-bh mw-list-item"><a href="https://bh.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%88%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A4%BF%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोटैक्टिनियम – Bhojpuri" lang="bh" hreflang="bh" data-title="प्रोटैक्टिनियम" data-language-autonym="भोजपुरी" data-language-local-name="Bhojpuri" class="interlanguage-link-target">भोजपुरी</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Bulgarian" lang="bg" hreflang="bg" data-title="Протактиний" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-bo mw-list-item"><a href="https://bo.wikipedia.org/wiki/%E0%BD%94%E0%BD%B4%E0%BC%8B%E0%BD%A2%E0%BD%BC%E0%BC%8B%E0%BD%8A%E0%BD%BA%E0%BD%82%E0%BC%8B%E0%BD%8A%E0%BD%B2%E0%BC%8B%E0%BD%93%E0%BD%B2%E0%BD%98%E0%BC%8D" title="པུ་རོ་ཊེག་ཊི་ནིམ། – Tibetan" lang="bo" hreflang="bo" data-title="པུ་རོ་ཊེག་ཊི་ནིམ།" data-language-autonym="བོད་ཡིག" data-language-local-name="Tibetan" class="interlanguage-link-target">བོད་ཡིག</a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Protaktinij" title="Protaktinij – Bosnian" lang="bs" hreflang="bs" data-title="Protaktinij" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target">Bosanski</a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Protaktiniom" title="Protaktiniom – Breton" lang="br" hreflang="br" data-title="Protaktiniom" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target">Brezhoneg</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Protoactini" title="Protoactini – Catalan" lang="ca" hreflang="ca" data-title="Protoactini" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Chuvash" lang="cv" hreflang="cv" data-title="Протактиний" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target">Чӑвашла</a></li><li class="interlanguage-link interwiki-ceb mw-list-item"><a href="https://ceb.wikipedia.org/wiki/Protactinyo" title="Protactinyo – Cebuano" lang="ceb" hreflang="ceb" data-title="Protactinyo" data-language-autonym="Cebuano" data-language-local-name="Cebuano" class="interlanguage-link-target">Cebuano</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Czech" lang="cs" hreflang="cs" data-title="Protaktinium" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-co mw-list-item"><a href="https://co.wikipedia.org/wiki/Protoattiniu" title="Protoattiniu – Corsican" lang="co" hreflang="co" data-title="Protoattiniu" data-language-autonym="Corsu" data-language-local-name="Corsican" class="interlanguage-link-target">Corsu</a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Protactiniwm" title="Protactiniwm – Welsh" lang="cy" hreflang="cy" data-title="Protactiniwm" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target">Cymraeg</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Protactinium" title="Protactinium – Danish" lang="da" hreflang="da" data-title="Protactinium" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D8%B7%D8%A7%D9%83%D8%AA%D9%8A%D9%86%D9%8A%D9%88%D9%85" title="پروطاكتينيوم – Moroccan Arabic" lang="ary" hreflang="ary" data-title="پروطاكتينيوم" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target">الدارجة</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Protactinium" title="Protactinium – German" lang="de" hreflang="de" data-title="Protactinium" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Protaktiinium" title="Protaktiinium – Estonian" lang="et" hreflang="et" data-title="Protaktiinium" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target">Eesti</a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A0%CF%81%CF%89%CF%84%CE%B1%CE%BA%CF%84%CE%AF%CE%BD%CE%B9%CE%BF" title="Πρωτακτίνιο – Greek" lang="el" hreflang="el" data-title="Πρωτακτίνιο" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target">Ελληνικά</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Protactinio" title="Protactinio – Spanish" lang="es" hreflang="es" data-title="Protactinio" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Protaktinio" title="Protaktinio – Esperanto" lang="eo" hreflang="eo" data-title="Protaktinio" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Protaktinio" title="Protaktinio – Basque" lang="eu" hreflang="eu" data-title="Protaktinio" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D8%AA%D8%A7%DA%A9%D8%AA%DB%8C%D9%86%DB%8C%D9%85" title="پروتاکتینیم – Persian" lang="fa" hreflang="fa" data-title="پروتاکتینیم" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-hif mw-list-item"><a href="https://hif.wikipedia.org/wiki/Protactinium" title="Protactinium – Fiji Hindi" lang="hif" hreflang="hif" data-title="Protactinium" data-language-autonym="Fiji Hindi" data-language-local-name="Fiji Hindi" class="interlanguage-link-target">Fiji Hindi</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Protactinium" title="Protactinium – French" lang="fr" hreflang="fr" data-title="Protactinium" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-fur mw-list-item"><a href="https://fur.wikipedia.org/wiki/Protoatini" title="Protoatini – Friulian" lang="fur" hreflang="fur" data-title="Protoatini" data-language-autonym="Furlan" data-language-local-name="Friulian" class="interlanguage-link-target">Furlan</a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Pr%C3%B3tachtainiam" title="Prótachtainiam – Irish" lang="ga" hreflang="ga" data-title="Prótachtainiam" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target">Gaeilge</a></li><li class="interlanguage-link interwiki-gv mw-list-item"><a href="https://gv.wikipedia.org/wiki/Protaghtinnium" title="Protaghtinnium – Manx" lang="gv" hreflang="gv" data-title="Protaghtinnium" data-language-autonym="Gaelg" data-language-local-name="Manx" class="interlanguage-link-target">Gaelg</a></li><li class="interlanguage-link interwiki-gd mw-list-item"><a href="https://gd.wikipedia.org/wiki/Protactinium" title="Protactinium – Scottish Gaelic" lang="gd" hreflang="gd" data-title="Protactinium" data-language-autonym="Gàidhlig" data-language-local-name="Scottish Gaelic" class="interlanguage-link-target">Gàidhlig</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Protactinio" title="Protactinio – Galician" lang="gl" hreflang="gl" data-title="Protactinio" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%AA%E0%AB%8D%E0%AA%B0%E0%AB%8B%E0%AA%9F%E0%AB%87%E0%AA%95%E0%AB%8D%E0%AA%9F%E0%AA%BF%E0%AA%A8%E0%AB%80%E0%AA%AF%E0%AA%AE" title="પ્રોટેક્ટિનીયમ – Gujarati" lang="gu" hreflang="gu" data-title="પ્રોટેક્ટિનીયમ" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target">ગુજરાતી</a></li><li class="interlanguage-link interwiki-hak mw-list-item"><a href="https://hak.wikipedia.org/wiki/Protactinium" title="Protactinium – Hakka Chinese" lang="hak" hreflang="hak" data-title="Protactinium" data-language-autonym="客家語 / Hak-kâ-ngî" data-language-local-name="Hakka Chinese" class="interlanguage-link-target">客家語 / Hak-kâ-ngî</a></li><li class="interlanguage-link interwiki-xal mw-list-item"><a href="https://xal.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D1%83%D0%BC" title="Протактиниум – Kalmyk" lang="xal" hreflang="xal" data-title="Протактиниум" data-language-autonym="Хальмг" data-language-local-name="Kalmyk" class="interlanguage-link-target">Хальмг</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%94%84%EB%A1%9C%ED%8A%B8%EC%95%85%ED%8B%B0%EB%8A%84" title="프로트악티늄 – Korean" lang="ko" hreflang="ko" data-title="프로트악티늄" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%8A%D6%80%D5%B8%D5%BF%D5%A1%D5%AF%D5%BF%D5%AB%D5%B6%D5%AB%D5%B8%D6%82%D5%B4" title="Պրոտակտինիում – Armenian" lang="hy" hreflang="hy" data-title="Պրոտակտինիում" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target">Հայերեն</a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%88%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A5%80%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोटैक्टीनियम – Hindi" lang="hi" hreflang="hi" data-title="प्रोटैक्टीनियम" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target">हिन्दी</a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Protaktinij" title="Protaktinij – Croatian" lang="hr" hreflang="hr" data-title="Protaktinij" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target">Hrvatski</a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Protaktinio" title="Protaktinio – Ido" lang="io" hreflang="io" data-title="Protaktinio" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target">Ido</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Indonesian" lang="id" hreflang="id" data-title="Protaktinium" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Protactinium" title="Protactinium – Interlingua" lang="ia" hreflang="ia" data-title="Protactinium" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target">Interlingua</a></li><li class="interlanguage-link interwiki-os mw-list-item"><a href="https://os.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Ossetic" lang="os" hreflang="os" data-title="Протактиний" data-language-autonym="Ирон" data-language-local-name="Ossetic" class="interlanguage-link-target">Ирон</a></li><li class="interlanguage-link interwiki-zu mw-list-item"><a href="https://zu.wikipedia.org/wiki/UmPhacagu" title="UmPhacagu – Zulu" lang="zu" hreflang="zu" data-title="UmPhacagu" data-language-autonym="IsiZulu" data-language-local-name="Zulu" class="interlanguage-link-target">IsiZulu</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Protoattinio" title="Protoattinio – Italian" lang="it" hreflang="it" data-title="Protoattinio" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A4%D7%A8%D7%95%D7%98%D7%A7%D7%98%D7%99%D7%A0%D7%99%D7%95%D7%9D" title="פרוטקטיניום – Hebrew" lang="he" hreflang="he" data-title="פרוטקטיניום" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Javanese" lang="jv" hreflang="jv" data-title="Protaktinium" data-language-autonym="Jawa" data-language-local-name="Javanese" class="interlanguage-link-target">Jawa</a></li><li class="interlanguage-link interwiki-kbp mw-list-item"><a href="https://kbp.wikipedia.org/wiki/Pr%C9%94tak%C9%A9t%C9%A9n%C9%A9y%C9%94m" title="Prɔtakɩtɩnɩyɔm – Kabiye" lang="kbp" hreflang="kbp" data-title="Prɔtakɩtɩnɩyɔm" data-language-autonym="Kabɩyɛ" data-language-local-name="Kabiye" class="interlanguage-link-target">Kabɩyɛ</a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%AA%E0%B3%8D%E0%B2%B0%E0%B3%8A%E0%B2%9F%E0%B2%BE%E0%B2%95%E0%B3%8D%E0%B2%9F%E0%B2%BF%E0%B2%A8%E0%B2%BF%E0%B2%AF%E0%B2%AE%E0%B3%8D" title="ಪ್ರೊಟಾಕ್ಟಿನಿಯಮ್ – Kannada" lang="kn" hreflang="kn" data-title="ಪ್ರೊಟಾಕ್ಟಿನಿಯಮ್" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target">ಕನ್ನಡ</a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%9E%E1%83%A0%E1%83%9D%E1%83%A2%E1%83%90%E1%83%A5%E1%83%A2%E1%83%98%E1%83%9C%E1%83%98%E1%83%A3%E1%83%9B%E1%83%98" title="პროტაქტინიუმი – Georgian" lang="ka" hreflang="ka" data-title="პროტაქტინიუმი" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target">ქართული</a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Kazakh" lang="kk" hreflang="kk" data-title="Протактиний" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target">Қазақша</a></li><li class="interlanguage-link interwiki-kw mw-list-item"><a href="https://kw.wikipedia.org/wiki/Protaktiniom" title="Protaktiniom – Cornish" lang="kw" hreflang="kw" data-title="Protaktiniom" data-language-autonym="Kernowek" data-language-local-name="Cornish" class="interlanguage-link-target">Kernowek</a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Protaktini" title="Protaktini – Swahili" lang="sw" hreflang="sw" data-title="Protaktini" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target">Kiswahili</a></li><li class="interlanguage-link interwiki-kv mw-list-item"><a href="https://kv.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Komi" lang="kv" hreflang="kv" data-title="Протактиний" data-language-autonym="Коми" data-language-local-name="Komi" class="interlanguage-link-target">Коми</a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Kyrgyz" lang="ky" hreflang="ky" data-title="Протактиний" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target">Кыргызча</a></li><li class="interlanguage-link interwiki-mrj mw-list-item"><a href="https://mrj.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Western Mari" lang="mrj" hreflang="mrj" data-title="Протактиний" data-language-autonym="Кырык мары" data-language-local-name="Western Mari" class="interlanguage-link-target">Кырык мары</a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Protactinium" title="Protactinium – Latin" lang="la" hreflang="la" data-title="Protactinium" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target">Latina</a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Protakt%C4%ABnijs" title="Protaktīnijs – Latvian" lang="lv" hreflang="lv" data-title="Protaktīnijs" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Protactinium" title="Protactinium – Luxembourgish" lang="lb" hreflang="lb" data-title="Protactinium" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target">Lëtzebuergesch</a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Protaktinis" title="Protaktinis – Lithuanian" lang="lt" hreflang="lt" data-title="Protaktinis" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target">Lietuvių</a></li><li class="interlanguage-link interwiki-lij mw-list-item"><a href="https://lij.wikipedia.org/wiki/Protoattinio" title="Protoattinio – Ligurian" lang="lij" hreflang="lij" data-title="Protoattinio" data-language-autonym="Ligure" data-language-local-name="Ligurian" class="interlanguage-link-target">Ligure</a></li><li class="interlanguage-link interwiki-li mw-list-item"><a href="https://li.wikipedia.org/wiki/Protactinium" title="Protactinium – Limburgish" lang="li" hreflang="li" data-title="Protactinium" data-language-autonym="Limburgs" data-language-local-name="Limburgish" class="interlanguage-link-target">Limburgs</a></li><li class="interlanguage-link interwiki-olo mw-list-item"><a href="https://olo.wikipedia.org/wiki/Protaktinii" title="Protaktinii – Livvi-Karelian" lang="olo" hreflang="olo" data-title="Protaktinii" data-language-autonym="Livvinkarjala" data-language-local-name="Livvi-Karelian" class="interlanguage-link-target">Livvinkarjala</a></li><li class="interlanguage-link interwiki-jbo mw-list-item"><a href="https://jbo.wikipedia.org/wiki/jinmrproktini" title="jinmrproktini – Lojban" lang="jbo" hreflang="jbo" data-title="jinmrproktini" data-language-autonym="La .lojban." data-language-local-name="Lojban" class="interlanguage-link-target">La .lojban.</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Protakt%C3%ADnium" title="Protaktínium – Hungarian" lang="hu" hreflang="hu" data-title="Protaktínium" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D1%83%D0%BC" title="Протактиниум – Macedonian" lang="mk" hreflang="mk" data-title="Протактиниум" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B5%8A%E0%B4%9F%E0%B5%8D%E0%B4%9F%E0%B4%95%E0%B5%8D%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B4%BF%E0%B4%A8%E0%B4%BF%E0%B4%AF%E0%B4%82" title="പ്രൊട്ടക്റ്റിനിയം – Malayalam" lang="ml" hreflang="ml" data-title="പ്രൊട്ടക്റ്റിനിയം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target">മലയാളം</a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%85%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A4%BF%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोटॅक्टिनियम – Marathi" lang="mr" hreflang="mr" data-title="प्रोटॅक्टिनियम" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target">मराठी</a></li><li class="interlanguage-link interwiki-arz mw-list-item"><a href="https://arz.wikipedia.org/wiki/%D8%A8%D8%B1%D9%88%D8%AA%D9%83%D8%AA%D9%8A%D9%86%D9%8A%D9%88%D9%85" title="بروتكتينيوم – Egyptian Arabic" lang="arz" hreflang="arz" data-title="بروتكتينيوم" data-language-autonym="مصرى" data-language-local-name="Egyptian Arabic" class="interlanguage-link-target">مصرى</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Malay" lang="ms" hreflang="ms" data-title="Protaktinium" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-cdo mw-list-item"><a href="https://cdo.wikipedia.org/wiki/Protactinium" title="Protactinium – Mindong" lang="cdo" hreflang="cdo" data-title="Protactinium" data-language-autonym="閩東語 / Mìng-dĕ̤ng-ngṳ̄" data-language-local-name="Mindong" class="interlanguage-link-target">閩東語 / Mìng-dĕ̤ng-ngṳ̄</a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8" title="Протактини – Mongolian" lang="mn" hreflang="mn" data-title="Протактини" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target">Монгол</a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%95%E1%80%9B%E1%80%AD%E1%80%AF%E1%80%90%E1%80%80%E1%80%BA%E1%80%90%E1%80%AE%E1%80%94%E1%80%AE%E1%80%9A%E1%80%99%E1%80%BA" title="ပရိုတက်တီနီယမ် – Burmese" lang="my" hreflang="my" data-title="ပရိုတက်တီနီယမ်" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target">မြန်မာဘာသာ</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Protactinium" title="Protactinium – Dutch" lang="nl" hreflang="nl" data-title="Protactinium" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-new mw-list-item"><a href="https://new.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A4%BF%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोट्याक्टिनियम – Newari" lang="new" hreflang="new" data-title="प्रोट्याक्टिनियम" data-language-autonym="नेपाल भाषा" data-language-local-name="Newari" class="interlanguage-link-target">नेपाल भाषा</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%97%E3%83%AD%E3%83%88%E3%82%A2%E3%82%AF%E3%83%81%E3%83%8B%E3%82%A6%E3%83%A0" title="プロトアクチニウム – Japanese" lang="ja" hreflang="ja" data-title="プロトアクチニウム" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-frr mw-list-item"><a href="https://frr.wikipedia.org/wiki/Protaktiinium" title="Protaktiinium – Northern Frisian" lang="frr" hreflang="frr" data-title="Protaktiinium" data-language-autonym="Nordfriisk" data-language-local-name="Northern Frisian" class="interlanguage-link-target">Nordfriisk</a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Protactinium" title="Protactinium – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Protactinium" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target">Norsk bokmål</a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Protactinium" title="Protactinium – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Protactinium" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-nov mw-list-item"><a href="https://nov.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Novial" lang="nov" hreflang="nov" data-title="Protaktinium" data-language-autonym="Novial" data-language-local-name="Novial" class="interlanguage-link-target">Novial</a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Protactini" title="Protactini – Occitan" lang="oc" hreflang="oc" data-title="Protactini" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target">Occitan</a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Protaktiniy" title="Protaktiniy – Uzbek" lang="uz" hreflang="uz" data-title="Protaktiniy" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target">Oʻzbekcha / ўзбекча</a></li><li class="interlanguage-link interwiki-pi mw-list-item"><a href="https://pi.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A4%BF%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोट्याक्टिनियम – Pali" lang="pi" hreflang="pi" data-title="प्रोट्याक्टिनियम" data-language-autonym="पालि" data-language-local-name="Pali" class="interlanguage-link-target">पालि</a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D9%B9%DB%8C%DA%A9%D9%B9%DB%8C%D9%86%DB%8C%D9%85" title="پروٹیکٹینیم – Western Punjabi" lang="pnb" hreflang="pnb" data-title="پروٹیکٹینیم" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target">پنجابی</a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D9%BC%DB%90%DA%A9%D9%BC%DB%90%D9%86%D9%8A%D9%88%D9%85" title="پروټېکټېنيوم – Pashto" lang="ps" hreflang="ps" data-title="پروټېکټېنيوم" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target">پښتو</a></li><li class="interlanguage-link interwiki-pms mw-list-item"><a href="https://pms.wikipedia.org/wiki/Protoactini" title="Protoactini – Piedmontese" lang="pms" hreflang="pms" data-title="Protoactini" data-language-autonym="Piemontèis" data-language-local-name="Piedmontese" class="interlanguage-link-target">Piemontèis</a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Protactinium" title="Protactinium – Low German" lang="nds" hreflang="nds" data-title="Protactinium" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target">Plattdüütsch</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Protaktyn" title="Protaktyn – Polish" lang="pl" hreflang="pl" data-title="Protaktyn" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Protact%C3%ADnio" title="Protactínio – Portuguese" lang="pt" hreflang="pt" data-title="Protactínio" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target">Português</a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Protactiniu" title="Protactiniu – Romanian" lang="ro" hreflang="ro" data-title="Protactiniu" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target">Română</a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Purutaktinyu" title="Purutaktinyu – Quechua" lang="qu" hreflang="qu" data-title="Purutaktinyu" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target">Runa Simi</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Russian" lang="ru" hreflang="ru" data-title="Протактиний" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-sah mw-list-item"><a href="https://sah.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D1%83%D0%BC" title="Протактиниум – Yakut" lang="sah" hreflang="sah" data-title="Протактиниум" data-language-autonym="Саха тыла" data-language-local-name="Yakut" class="interlanguage-link-target">Саха тыла</a></li><li class="interlanguage-link interwiki-sa mw-list-item"><a href="https://sa.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%95%E0%A5%8D%E0%A4%9F%E0%A4%BF%E0%A4%A8%E0%A4%BF%E0%A4%AF%E0%A4%AE" title="प्रोट्याक्टिनियम – Sanskrit" lang="sa" hreflang="sa" data-title="प्रोट्याक्टिनियम" data-language-autonym="संस्कृतम्" data-language-local-name="Sanskrit" class="interlanguage-link-target">संस्कृतम्</a></li><li class="interlanguage-link interwiki-sc mw-list-item"><a href="https://sc.wikipedia.org/wiki/Protoat%C3%ACniu" title="Protoatìniu – Sardinian" lang="sc" hreflang="sc" data-title="Protoatìniu" data-language-autonym="Sardu" data-language-local-name="Sardinian" class="interlanguage-link-target">Sardu</a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Protactinium" title="Protactinium – Scots" lang="sco" hreflang="sco" data-title="Protactinium" data-language-autonym="Scots" data-language-local-name="Scots" class="interlanguage-link-target">Scots</a></li><li class="interlanguage-link interwiki-stq mw-list-item"><a href="https://stq.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Saterland Frisian" lang="stq" hreflang="stq" data-title="Protaktinium" data-language-autonym="Seeltersk" data-language-local-name="Saterland Frisian" class="interlanguage-link-target">Seeltersk</a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Protaktini" title="Protaktini – Albanian" lang="sq" hreflang="sq" data-title="Protaktini" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target">Shqip</a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Protoattiniu" title="Protoattiniu – Sicilian" lang="scn" hreflang="scn" data-title="Protoattiniu" data-language-autonym="Sicilianu" data-language-local-name="Sicilian" class="interlanguage-link-target">Sicilianu</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Protactinium" title="Protactinium – Simple English" lang="en-simple" hreflang="en-simple" data-title="Protactinium" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sd mw-list-item"><a href="https://sd.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D9%BD%D9%8A%DA%AA%D9%BD%D9%8A%D9%86%D9%8A%D9%85" title="پروٽيڪٽينيم – Sindhi" lang="sd" hreflang="sd" data-title="پروٽيڪٽينيم" data-language-autonym="سنڌي" data-language-local-name="Sindhi" class="interlanguage-link-target">سنڌي</a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Protakt%C3%ADnium" title="Protaktínium – Slovak" lang="sk" hreflang="sk" data-title="Protaktínium" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target">Slovenčina</a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Protaktinij" title="Protaktinij – Slovenian" lang="sl" hreflang="sl" data-title="Protaktinij" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%BE%D8%B1%DB%86%D8%AA%DB%95%DA%A9%D8%AA%DB%8C%D9%86%DB%8C%DB%86%D9%85" title="پرۆتەکتینیۆم – Central Kurdish" lang="ckb" hreflang="ckb" data-title="پرۆتەکتینیۆم" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target">کوردی</a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D1%98%D1%83%D0%BC" title="Протактинијум – Serbian" lang="sr" hreflang="sr" data-title="Протактинијум" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target">Српски / srpski</a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Protaktinijum" title="Protaktinijum – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Protaktinijum" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target">Srpskohrvatski / српскохрватски</a></li><li class="interlanguage-link interwiki-fi badge-Q17559452 badge-recommendedarticle mw-list-item" title="recommended article"><a href="https://fi.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Finnish" lang="fi" hreflang="fi" data-title="Protaktinium" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target">Suomi</a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Protaktinium" title="Protaktinium – Swedish" lang="sv" hreflang="sv" data-title="Protaktinium" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Protaktinyo" title="Protaktinyo – Tagalog" lang="tl" hreflang="tl" data-title="Protaktinyo" data-language-autonym="Tagalog" data-language-local-name="Tagalog" class="interlanguage-link-target">Tagalog</a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%AA%E0%AF%81%E0%AE%B0%E0%AF%8B%E0%AE%9F%E0%AE%BE%E0%AE%95%E0%AF%8D%E0%AE%9F%E0%AE%BF%E0%AE%A9%E0%AE%BF%E0%AE%AF%E0%AE%AE%E0%AF%8D" title="புரோடாக்டினியம் – Tamil" lang="ta" hreflang="ta" data-title="புரோடாக்டினியம்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target">தமிழ்</a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Tatar" lang="tt" hreflang="tt" data-title="Протактиний" data-language-autonym="Татарча / tatarça" data-language-local-name="Tatar" class="interlanguage-link-target">Татарча / tatarça</a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%AA%E0%B1%8D%E0%B0%B0%E0%B1%8A%E0%B0%9F%E0%B0%BE%E0%B0%95%E0%B1%8D%E0%B0%9F%E0%B1%80%E0%B0%A8%E0%B0%BF%E0%B0%AF%E0%B0%82" title="ప్రొటాక్టీనియం – Telugu" lang="te" hreflang="te" data-title="ప్రొటాక్టీనియం" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target">తెలుగు</a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B9%82%E0%B8%9E%E0%B8%A3%E0%B9%81%E0%B8%97%E0%B8%81%E0%B8%97%E0%B8%B4%E0%B9%80%E0%B8%99%E0%B8%B5%E0%B8%A2%E0%B8%A1" title="โพรแทกทิเนียม – Thai" lang="th" hreflang="th" data-title="โพรแทกทิเนียม" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target">ไทย</a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D0%B8%D0%B9" title="Протактиний – Tajik" lang="tg" hreflang="tg" data-title="Протактиний" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target">Тоҷикӣ</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Protaktinyum" title="Protaktinyum – Turkish" lang="tr" hreflang="tr" data-title="Protaktinyum" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D1%82%D0%B0%D0%BA%D1%82%D0%B8%D0%BD%D1%96%D0%B9" title="Протактиній – Ukrainian" lang="uk" hreflang="uk" data-title="Протактиній" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D9%B9%DB%8C%DA%A9%D9%B9%DB%8C%D9%86%DB%8C%D9%85" title="پروٹیکٹینیم – Urdu" lang="ur" hreflang="ur" data-title="پروٹیکٹینیم" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target">اردو</a></li><li class="interlanguage-link interwiki-ug mw-list-item"><a href="https://ug.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D8%AA%D8%A7%D9%83%D8%AA%D9%89%D9%86%D9%89%D9%8A" title="پروتاكتىنىي – Uyghur" lang="ug" hreflang="ug" data-title="پروتاكتىنىي" data-language-autonym="ئۇيغۇرچە / Uyghurche" data-language-local-name="Uyghur" class="interlanguage-link-target">ئۇيغۇرچە / Uyghurche</a></li><li class="interlanguage-link interwiki-vep mw-list-item"><a href="https://vep.wikipedia.org/wiki/Protaktinii" title="Protaktinii – Veps" lang="vep" hreflang="vep" data-title="Protaktinii" data-language-autonym="Vepsän kel’" data-language-local-name="Veps" class="interlanguage-link-target">Vepsän kel’</a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Protactini" title="Protactini – Vietnamese" lang="vi" hreflang="vi" data-title="Protactini" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target">Tiếng Việt</a></li><li class="interlanguage-link interwiki-zh-classical mw-list-item"><a href="https://zh-classical.wikipedia.org/wiki/%E9%8F%B7" title="鏷 – Literary Chinese" lang="lzh" hreflang="lzh" data-title="鏷" data-language-autonym="文言" data-language-local-name="Literary Chinese" class="interlanguage-link-target">文言</a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Protactinyo" title="Protactinyo – Waray" lang="war" hreflang="war" data-title="Protactinyo" data-language-autonym="Winaray" data-language-local-name="Waray" class="interlanguage-link-target">Winaray</a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E9%95%A4" title="镤 – Wu" lang="wuu" hreflang="wuu" data-title="镤" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target">吴语</a></li><li class="interlanguage-link interwiki-yo mw-list-item"><a href="https://yo.wikipedia.org/wiki/Protaktin%C3%AD%E1%BB%8D%CC%80m" title="Protaktiníọ̀m – Yoruba" lang="yo" hreflang="yo" data-title="Protaktiníọ̀m" data-language-autonym="Yorùbá" data-language-local-name="Yoruba" class="interlanguage-link-target">Yorùbá</a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E9%8F%B7" title="鏷 – Cantonese" lang="yue" hreflang="yue" data-title="鏷" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target">粵語</a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E9%95%A4" title="镤 – Chinese" lang="zh" hreflang="zh" data-title="镤" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target">中文</a></li> </ul> <div class="after-portlet after-portlet-lang"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1109#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Protactinium" title="View the content page [c]" accesskey="c">Article</a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Protactinium" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t">Talk</a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" >English </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Protactinium">Read</a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Protactinium&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Protactinium&action=history" title="Past revisions of this page [h]" accesskey="h">View history</a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" >Tools </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Protactinium">Read</a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Protactinium&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Protactinium&action=history">View history</a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Protactinium" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j">What links here</a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Protactinium" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k">Related changes</a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u">Upload file</a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q">Special pages</a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Protactinium&oldid=1274596214" title="Permanent link to this revision of this page">Permanent link</a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Protactinium&action=info" title="More information about this page">Page information</a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Protactinium&id=1274596214&wpFormIdentifier=titleform" title="Information on how to cite this page">Cite this page</a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FProtactinium">Get shortened URL</a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FProtactinium">Download QR code</a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Protactinium&action=show-download-screen" title="Download this page as a PDF file">Download as PDF</a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Protactinium&printable=yes" title="Printable version of this page [p]" accesskey="p">Printable version</a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Protactinium" hreflang="en">Wikimedia Commons</a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1109" title="Structured data on this page hosted by Wikidata [g]" accesskey="g">Wikidata item</a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> <div id="mw-indicator-good-star" class="mw-indicator"><div class="mw-parser-output"><a href="/wiki/Wikipedia:Good_articles*" title="This is a good article. Click here for more information."><img alt="This is a good article. Click here for more information." src="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/19px-Symbol_support_vote.svg.png" decoding="async" width="19" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/29px-Symbol_support_vote.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/39px-Symbol_support_vote.svg.png 2x" data-file-width="180" data-file-height="185" /></a></div></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"> <div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical element with atomic number 91 (Pa)</div><style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><style data-mw-deduplicate="TemplateStyles:r1158442001">body.skin-minerva .mw-parser-output .infobox-full-data>.wikitable,body.skin-minerva .mw-parser-output .infobox .periodictable{display:table}body.skin-minerva .mw-parser-output .infobox-full-data{width:calc(100% - 20px)}body.skin-minerva .mw-parser-output .infobox-full-data>div{max-width:100%;overflow:auto}body.skin-minerva .mw-parser-output .infobox caption{display:table-caption}</style><table class="infobox"><caption class="infobox-title">Protactinium, 91Pa</caption><tbody><tr><td colspan="2" class="infobox-image"><a href="/wiki/File:Protactinium_(Element_-_91)_2.jpg" class="mw-file-description"><img alt="Small (a few cm) piece of silvery-gray metal in a sealed vial" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/220px-Protactinium_%28Element_-_91%29_2.jpg" decoding="async" width="220" height="176" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/330px-Protactinium_%28Element_-_91%29_2.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ea/Protactinium_%28Element_-_91%29_2.jpg/440px-Protactinium_%28Element_-_91%29_2.jpg 2x" data-file-width="1562" data-file-height="1253" /></a><div class="infobox-caption">Sample of a protactinium-231 in a glass vial</div></td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Protactinium</th></tr><tr><th scope="row" class="infobox-label">Pronunciation</th><td class="infobox-data"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/ˌproʊtækˈtɪniəm/</a> (<a href="/wiki/Help:Pronunciation_respelling_key" title="Help:Pronunciation respelling key">PROH-tak-TIN-ee-əm</a>)</td></tr><tr><th scope="row" class="infobox-label">Appearance</th><td class="infobox-data">bright, silvery metallic luster</td></tr><tr><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546"></td></tr><tr><th colspan="2" class="infobox-header" style="text-align: left; color:inherit; background: transparent;"><a href="/wiki/Standard_atomic_weight" title="Standard atomic weight">Standard atomic weight</a> <style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style>Ar°(Pa)</th></tr><tr><th scope="row" class="infobox-label"></th><td class="infobox-data"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li>231.03588±0.00001<a href="#cite_note-CIAAW-1">[1]</a></li><li>231.04±0.01 (<a href="/wiki/Standard_atomic_weight#Abridged_atomic_weight" title="Standard atomic weight">abridged</a>)<a href="#cite_note-CIAAW2021-2">[2]</a></li></ul></div></td></tr><tr style="display:none"><td colspan="2"> </td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Protactinium in the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a></th></tr><tr><td colspan="2" class="infobox-full-data"> <table class="wikitable" style="text-align:center; width:100%; margin:0;"> <tbody><tr> <td> <table class="periodictable" style="margin:0 auto"> <tbody><tr> <td style="border:none; width:5px"><div style="background-color:transparent; color:inherit; margin:0; padding:0; text-align:center; border:none;"> <table style="empty-cells:hidden; border:none; padding:0; border-spacing:1px; border-collapse:separate; margin:0;"> <tbody><tr> <td style="border:none;padding:0;"><a href="/wiki/Hydrogen" title="Hydrogen">Hydrogen</a> </td> <td colspan="30" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Helium" title="Helium">Helium</a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Lithium" title="Lithium">Lithium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Beryllium" title="Beryllium">Beryllium</a> </td> <td colspan="24" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Boron" title="Boron">Boron</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Carbon" title="Carbon">Carbon</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nitrogen" title="Nitrogen">Nitrogen</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Oxygen" title="Oxygen">Oxygen</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Fluorine" title="Fluorine">Fluorine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neon" title="Neon">Neon</a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Sodium" title="Sodium">Sodium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Magnesium" title="Magnesium">Magnesium</a> </td> <td colspan="24" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Aluminium" title="Aluminium">Aluminium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Silicon" title="Silicon">Silicon</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Phosphorus" title="Phosphorus">Phosphorus</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Sulfur" title="Sulfur">Sulfur</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Chlorine" title="Chlorine">Chlorine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Argon" title="Argon">Argon</a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Potassium" title="Potassium">Potassium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Calcium" title="Calcium">Calcium</a> </td> <td colspan="14" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Scandium" title="Scandium">Scandium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Titanium" title="Titanium">Titanium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Vanadium" title="Vanadium">Vanadium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Chromium" title="Chromium">Chromium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Manganese" title="Manganese">Manganese</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iron" title="Iron">Iron</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cobalt" title="Cobalt">Cobalt</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nickel" title="Nickel">Nickel</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Copper" title="Copper">Copper</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Zinc" title="Zinc">Zinc</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gallium" title="Gallium">Gallium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Germanium" title="Germanium">Germanium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Arsenic" title="Arsenic">Arsenic</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Selenium" title="Selenium">Selenium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bromine" title="Bromine">Bromine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Krypton" title="Krypton">Krypton</a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Rubidium" title="Rubidium">Rubidium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Strontium" title="Strontium">Strontium</a> </td> <td style="border:none;padding:0;; width:0;"> </td> <td colspan="13" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Yttrium" title="Yttrium">Yttrium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Zirconium" title="Zirconium">Zirconium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Niobium" title="Niobium">Niobium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Molybdenum" title="Molybdenum">Molybdenum</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Technetium" title="Technetium">Technetium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Ruthenium" title="Ruthenium">Ruthenium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rhodium" title="Rhodium">Rhodium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Palladium" title="Palladium">Palladium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Silver" title="Silver">Silver</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cadmium" title="Cadmium">Cadmium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Indium" title="Indium">Indium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tin" title="Tin">Tin</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Antimony" title="Antimony">Antimony</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tellurium" title="Tellurium">Tellurium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iodine" title="Iodine">Iodine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Xenon" title="Xenon">Xenon</a> </td></tr> <tr style="border:none;padding:0;"> <td style="border:none;padding:0;"><a href="/wiki/Caesium" title="Caesium">Caesium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Barium" title="Barium">Barium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lanthanum" title="Lanthanum">Lanthanum</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cerium" title="Cerium">Cerium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Praseodymium" title="Praseodymium">Praseodymium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neodymium" title="Neodymium">Neodymium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Promethium" title="Promethium">Promethium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Samarium" title="Samarium">Samarium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Europium" title="Europium">Europium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gadolinium" title="Gadolinium">Gadolinium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Terbium" title="Terbium">Terbium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Dysprosium" title="Dysprosium">Dysprosium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Holmium" title="Holmium">Holmium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Erbium" title="Erbium">Erbium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thulium" title="Thulium">Thulium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Ytterbium" title="Ytterbium">Ytterbium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lutetium" title="Lutetium">Lutetium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Hafnium" title="Hafnium">Hafnium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tantalum" title="Tantalum">Tantalum</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tungsten" title="Tungsten">Tungsten</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rhenium" title="Rhenium">Rhenium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Osmium" title="Osmium">Osmium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iridium" title="Iridium">Iridium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Platinum" title="Platinum">Platinum</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gold" title="Gold">Gold</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Mercury_(element)" title="Mercury (element)">Mercury (element)</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thallium" title="Thallium">Thallium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lead" title="Lead">Lead</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bismuth" title="Bismuth">Bismuth</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Polonium" title="Polonium">Polonium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Astatine" title="Astatine">Astatine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Radon" title="Radon">Radon</a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Francium" title="Francium">Francium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Radium" title="Radium">Radium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Actinium" title="Actinium">Actinium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thorium" title="Thorium">Thorium</a> </td> <td style="border:none;padding:0;"><a class="mw-selflink selflink">Protactinium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Uranium" title="Uranium">Uranium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neptunium" title="Neptunium">Neptunium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Plutonium" title="Plutonium">Plutonium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Americium" title="Americium">Americium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Curium" title="Curium">Curium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Berkelium" title="Berkelium">Berkelium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Californium" title="Californium">Californium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Einsteinium" title="Einsteinium">Einsteinium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Fermium" title="Fermium">Fermium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Mendelevium" title="Mendelevium">Mendelevium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nobelium" title="Nobelium">Nobelium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lawrencium" title="Lawrencium">Lawrencium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rutherfordium" title="Rutherfordium">Rutherfordium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Dubnium" title="Dubnium">Dubnium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Seaborgium" title="Seaborgium">Seaborgium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bohrium" title="Bohrium">Bohrium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Hassium" title="Hassium">Hassium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Meitnerium" title="Meitnerium">Meitnerium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Darmstadtium" title="Darmstadtium">Darmstadtium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Roentgenium" title="Roentgenium">Roentgenium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Copernicium" title="Copernicium">Copernicium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nihonium" title="Nihonium">Nihonium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Flerovium" title="Flerovium">Flerovium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Moscovium" title="Moscovium">Moscovium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Livermorium" title="Livermorium">Livermorium</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tennessine" title="Tennessine">Tennessine</a> </td> <td style="border:none;padding:0;"><a href="/wiki/Oganesson" title="Oganesson">Oganesson</a> </td></tr></tbody></table> </div> </td> <td style="vertical-align:middle; text-align:center; font-size:90%; line-height:100%; width:10px; border:none;"><a href="/wiki/Praseodymium" title="Praseodymium">Pr</a> ↑ Pa ↓ — </td></tr> <tr> <td colspan="2" class="nowrap" style="text-align:center; font-size:90%; line-height:100%; padding-top:0; padding-bottom:1px; border:none;"><a href="/wiki/Thorium" title="Thorium">thorium</a> ← protactinium → <a href="/wiki/Uranium" title="Uranium">uranium</a> </td></tr></tbody></table> </td></tr></tbody></table></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Atomic_number" title="Atomic number">Atomic number</a> (Z)</th><td class="infobox-data">91</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Group_(periodic_table)" title="Group (periodic table)">Group</a></th><td class="infobox-data"><a href="/wiki/F-block_groups" class="mw-redirect" title="F-block groups">f-block groups</a> (no number)</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Period_(periodic_table)" title="Period (periodic table)">Period</a></th><td class="infobox-data"><a href="/wiki/Period_7_element" title="Period 7 element">period 7</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Block_(periodic_table)" title="Block (periodic table)">Block</a></th><td class="infobox-data">  <a href="/wiki/Block_(periodic_table)#f-block" title="Block (periodic table)">f-block</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Electron_configuration" title="Electron configuration">Electron configuration</a></th><td class="infobox-data">[<a href="/wiki/Radon" title="Radon">Rn</a>] 5f2 6d1 7s2</td></tr><tr><th scope="row" class="infobox-label">Electrons per shell</th><td class="infobox-data">2, 8, 18, 32, 20, 9, 2</td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Physical properties</th></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Phase_(matter)" title="Phase (matter)">Phase</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488">at <a href="/wiki/Standard_temperature_and_pressure" title="Standard temperature and pressure">STP</a></th><td class="infobox-data"><a href="/wiki/Solid" title="Solid">solid</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Melting_point" title="Melting point">Melting point</a></th><td class="infobox-data">1841 <a href="/wiki/Kelvin" title="Kelvin">K</a> (1568 °C, 2854 °F) </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Boiling_point" title="Boiling point">Boiling point</a></th><td class="infobox-data">4300 K (4027 °C, 7280 °F) (?)</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Density" title="Density">Density</a> (at 20° C)</th><td class="infobox-data">15.43 g/cm3 <a href="#cite_note-Arblaster_2018-3">[3]</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Enthalpy_of_fusion" title="Enthalpy of fusion">Heat of fusion</a></th><td class="infobox-data">12.34 <a href="/wiki/Kilojoule_per_mole" class="mw-redirect" title="Kilojoule per mole">kJ/mol</a> </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Enthalpy_of_vaporization" title="Enthalpy of vaporization">Heat of vaporization</a></th><td class="infobox-data">481 kJ/mol </td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Atomic properties</th></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Oxidation_state" title="Oxidation state">Oxidation states</a></th><td class="infobox-data">common: +5 +2,<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">?</a> +3,<a href="#cite_note-GE28-4">[4]</a> +4<a href="#cite_note-GE28-4">[4]</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Electronegativity" title="Electronegativity">Electronegativity</a></th><td class="infobox-data">Pauling scale: 1.5 </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Ionization_energy" title="Ionization energy">Ionization energies</a></th><td class="infobox-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li>1st: 568 kJ/mol </li><li> </li></ul></div></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Atomic_radius" title="Atomic radius">Atomic radius</a></th><td class="infobox-data">empirical: 163 <a href="/wiki/Picometre" title="Picometre">pm</a> </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Covalent_radius" title="Covalent radius">Covalent radius</a></th><td class="infobox-data">200 pm </td></tr><tr><td colspan="2" class="infobox-full-data"><figure class="mw-default-size mw-halign-center" typeof="mw:File/Frameless"><a href="/wiki/File:91_(Pa_I)_NIST_ASD_emission_spectrum.png" class="mw-file-description"><img alt="Color lines in a spectral range" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e9/91_%28Pa_I%29_NIST_ASD_emission_spectrum.png/240px-91_%28Pa_I%29_NIST_ASD_emission_spectrum.png" decoding="async" width="240" height="29" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e9/91_%28Pa_I%29_NIST_ASD_emission_spectrum.png/360px-91_%28Pa_I%29_NIST_ASD_emission_spectrum.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e9/91_%28Pa_I%29_NIST_ASD_emission_spectrum.png/480px-91_%28Pa_I%29_NIST_ASD_emission_spectrum.png 2x" data-file-width="4000" data-file-height="480" /></a><figcaption></figcaption></figure><a href="/wiki/Spectral_line" title="Spectral line">Spectral lines</a> of protactinium</td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">Other properties</th></tr><tr><th scope="row" class="infobox-label">Natural occurrence</th><td class="infobox-data"><a href="/wiki/Trace_radioisotope" title="Trace radioisotope">from decay</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Crystal_structure" title="Crystal structure">Crystal structure</a></th><td class="infobox-data"> <a href="/wiki/Tetragonal_crystal_system" title="Tetragonal crystal system">body-centered tetragonal</a><a href="#cite_note-str-5">[5]</a> (<a href="/wiki/Pearson_symbol" title="Pearson symbol">tI2</a>)</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Lattice_constant" title="Lattice constant">Lattice constant</a></th><td class="infobox-data"><div style="float:right;"><a href="/wiki/File:Body-centered_tetragonal.svg" class="mw-file-description"><img alt="Body-centered tetragonal crystal structure for protactinium" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Body-centered_tetragonal.svg/50px-Body-centered_tetragonal.svg.png" decoding="async" width="50" height="76" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Body-centered_tetragonal.svg/75px-Body-centered_tetragonal.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Body-centered_tetragonal.svg/100px-Body-centered_tetragonal.svg.png 2x" data-file-width="108" data-file-height="165" /></a></div>a = 392.1 pm c = 323.5 pm (at 20 °C)<a href="#cite_note-Arblaster_2018-3">[3]</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Coefficient_of_thermal_expansion" class="mw-redirect" title="Coefficient of thermal expansion">Thermal expansion</a></th><td class="infobox-data">11.8×10−6/K (at 20 °C)<a href="#cite_note-Arblaster_2018-3">[3]</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Thermal_conductivity" class="mw-redirect" title="Thermal conductivity">Thermal conductivity</a></th><td class="infobox-data">47 W/(m⋅K) </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Electrical_resistivity_and_conductivity" title="Electrical resistivity and conductivity">Electrical resistivity</a></th><td class="infobox-data">177 nΩ⋅m (at 0 °C) </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Magnetism" title="Magnetism">Magnetic ordering</a></th><td class="infobox-data"><a href="/wiki/Paramagnetic" class="mw-redirect" title="Paramagnetic">paramagnetic</a><a href="#cite_note-magnet-6">[6]</a> </td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/CAS_Registry_Number" title="CAS Registry Number">CAS Number</a></th><td class="infobox-data">7440-13-3 </td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99">History</th></tr><tr><th scope="row" class="infobox-label">Prediction</th><td class="infobox-data"><a href="/wiki/Dmitri_Mendeleev" title="Dmitri Mendeleev">Dmitri Mendeleev</a> (1869)</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Timeline_of_chemical_element_discoveries" class="mw-redirect" title="Timeline of chemical element discoveries">Discovery</a> and first isolation</th><td class="infobox-data"><a href="/wiki/Kasimir_Fajans" class="mw-redirect" title="Kasimir Fajans">Kasimir Fajans</a> and <a href="/wiki/Oswald_Helmuth_G%C3%B6hring" title="Oswald Helmuth Göhring">Oswald Helmuth Göhring</a> (1913)</td></tr><tr><th scope="row" class="infobox-label">Named by</th><td class="infobox-data"><a href="/wiki/Otto_Hahn" title="Otto Hahn">Otto Hahn</a> and <a href="/wiki/Lise_Meitner" title="Lise Meitner">Lise Meitner</a> (1917–8)</td></tr><tr><th colspan="2" class="infobox-header" style="color:inherit; background:#9bff99"><a href="/wiki/Isotopes_of_protactinium" title="Isotopes of protactinium">Isotopes of protactinium</a><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Infobox_protactinium_isotopes" title="Template:Infobox protactinium isotopes"><abbr title="View this template">v</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Infobox_protactinium_isotopes" title="Special:EditPage/Template:Infobox protactinium isotopes"><abbr title="Edit this template">e</abbr></a></li></ul></div></th></tr><tr><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546"></td></tr><tr><td colspan="2" class="infobox-full-data"> <table class="wikitable" style="text-align: center; vertical-align: middle; width: 100%; border-collapse: collapse; margin: 0; padding: 0;"> <tbody><tr> <th colspan="3">Main isotopes<a href="#cite_note-NUBASE2020-7">[7]</a> </th> <th colspan="2"><a href="/wiki/Radioactive_decay" title="Radioactive decay">Decay</a> </th></tr> <tr> <th> </th> <th style="padding: 0.1em;"><a href="/wiki/Natural_abundance" title="Natural abundance">abundance</a> </th> <th style="padding: 0.1em;"><a href="/wiki/Half-life" title="Half-life">half-life</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488">(t1/2) </th> <th style="padding: 0.1em;"><a href="/wiki/Radioactive_decay#Types_of_decay" title="Radioactive decay">mode</a> </th> <th style="padding: 0.1em;"><a href="/wiki/Decay_product" title="Decay product">product</a> </th></tr> <tr> <th rowspan="1" style="vertical-align: top;">229Pa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;"><a href="/wiki/Synthetic_radioisotope" title="Synthetic radioisotope">synth</a> </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">1.5 d </td> <td style="text-align: left; vertical-align: top;"><a href="/wiki/Electron_capture" title="Electron capture">ε</a> </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Thorium-229" class="mw-redirect" title="Thorium-229">229Th</a> </td></tr> <tr> <th rowspan="3" style="vertical-align: top;">230Pa </th> <td rowspan="3" colspan="1" style="vertical-align: top; text-align: center;">synth </td> <td rowspan="3" colspan="1" style="vertical-align: top; text-align: right;">17.4 d </td> <td style="text-align: left; vertical-align: top;"><a href="/wiki/Beta_plus_decay" class="mw-redirect" title="Beta plus decay">β+</a> </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Thorium-230" class="mw-redirect" title="Thorium-230">230Th</a> </td></tr> <tr> <td style="text-align: left; vertical-align: top;"><a href="/wiki/Beta_minus_decay" class="mw-redirect" title="Beta minus decay">β−</a> </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Uranium-230" class="mw-redirect" title="Uranium-230">230U</a> </td></tr> <tr> <td style="text-align: left; vertical-align: top;"><a href="/wiki/Alpha_decay" title="Alpha decay">α</a> </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Actinium-226" class="mw-redirect" title="Actinium-226">226Ac</a> </td></tr> <tr> <th rowspan="1" style="vertical-align: top;">231Pa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">100% </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">3.265×104 y </td> <td style="text-align: left; vertical-align: top;">α </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Actinium-227" class="mw-redirect" title="Actinium-227">227Ac</a> </td></tr> <tr> <th rowspan="1" style="vertical-align: top;">232Pa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;">synth </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">1.32 d </td> <td style="text-align: left; vertical-align: top;">β− </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Uranium-232" title="Uranium-232">232U</a> </td></tr> <tr> <th rowspan="1" style="vertical-align: top;">233Pa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;"><a href="/wiki/Trace_radioisotope" title="Trace radioisotope">trace</a> </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">26.975 d </td> <td style="text-align: left; vertical-align: top;">β− </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Uranium-233" title="Uranium-233">233U</a> </td></tr> <tr> <th rowspan="1" style="vertical-align: top;">234Pa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;">trace </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">6.70 h </td> <td style="text-align: left; vertical-align: top;">β− </td> <td style="text-align: right; vertical-align: middle;"><a href="/wiki/Uranium-234" title="Uranium-234">234U</a> </td></tr> <tr> <th rowspan="1" style="vertical-align: top;">234mPa </th> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: center;">trace </td> <td rowspan="1" colspan="1" style="vertical-align: top; text-align: right;">1.159 min </td> <td style="text-align: left; vertical-align: top;">β− </td> <td style="text-align: right; vertical-align: middle;">234U </td></tr></tbody></table></td></tr><tr style="display:none"><td colspan="2"> </td></tr><tr><td colspan="2" class="infobox-below noprint" style="color:inherit; background:#9bff99"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Category:Protactinium" title="Category:Protactinium">Category: Protactinium</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist"><ul><li class="nv-view"><a href="/wiki/Template:Infobox_protactinium" title="Template:Infobox protactinium">view</a></li><li class="nv-talk"><a href="/wiki/Template_talk:Infobox_protactinium" title="Template talk:Infobox protactinium">talk</a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Infobox_protactinium" title="Special:EditPage/Template:Infobox protactinium">edit</a></li></ul></div> | <a href="/wiki/List_of_data_references_for_chemical_elements" title="List of data references for chemical elements">references</a></td></tr></tbody></table> Protactinium is a <a href="/wiki/Chemical_element" title="Chemical element">chemical element</a>; it has <a href="/wiki/Chemical_symbol" title="Chemical symbol">symbol</a> Pa and <a href="/wiki/Atomic_number" title="Atomic number">atomic number</a> 91. It is a dense, <a href="/wiki/Radioactive" class="mw-redirect" title="Radioactive">radioactive</a>, silvery-gray <a href="/wiki/Actinide" title="Actinide">actinide</a> metal which readily reacts with <a href="/wiki/Oxygen" title="Oxygen">oxygen</a>, water vapor, and inorganic <a href="/wiki/Acid" title="Acid">acids</a>. It forms various <a href="/wiki/Chemical_compound" title="Chemical compound">chemical compounds</a>, in which protactinium is usually present in the <a href="/wiki/Oxidation_state" title="Oxidation state">oxidation state</a> +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some <a href="/wiki/Uraninite" title="Uraninite">uraninite</a> ore deposits. Because of its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from <a href="/wiki/Spent_nuclear_fuel" title="Spent nuclear fuel">spent nuclear fuel</a>. The element was first identified in 1913 by <a href="/wiki/Kazimierz_Fajans" title="Kazimierz Fajans">Kazimierz Fajans</a> and <a href="/wiki/Oswald_Helmuth_G%C3%B6hring" title="Oswald Helmuth Göhring">Oswald Helmuth Göhring</a> and named "brevium" because of the short <a href="/wiki/Half-life" title="Half-life">half-life</a> of the specific <a href="/wiki/Isotope" title="Isotope">isotope</a> studied, protactinium-234<a href="/wiki/Nuclear_isomer" title="Nuclear isomer">m</a>. A more stable isotope of protactinium, 231Pa, was discovered in 1917/18 by <a href="/wiki/Lise_Meitner" title="Lise Meitner">Lise Meitner</a> in collaboration with <a href="/wiki/Otto_Hahn" title="Otto Hahn">Otto Hahn</a>, and they named the element protactinium.<a href="#cite_note-meitner-8">[8]</a> In 1949, the <a href="/wiki/IUPAC" class="mw-redirect" title="IUPAC">IUPAC</a> chose the name "protactinium" and confirmed Hahn and Meitner as its discoverers. The new name meant "(nuclear) <a href="/wiki/Precursor_(chemistry)" title="Precursor (chemistry)">precursor</a> of <a href="/wiki/Actinium" title="Actinium">actinium</a>,"<a href="#cite_note-9">[9]</a> suggesting that actinium is a product of radioactive decay of protactinium. <a href="/wiki/John_Arnold_Cranston" title="John Arnold Cranston">John Arnold Cranston</a> (working with <a href="/wiki/Frederick_Soddy" title="Frederick Soddy">Frederick Soddy</a> and <a href="/wiki/Ada_Hitchins" title="Ada Hitchins">Ada Hitchins</a>) is also credited with discovering the most stable isotope in 1915, but he delayed his announcement due to being called for service in the <a href="/wiki/First_World_War" class="mw-redirect" title="First World War">First World War</a>.<a href="#cite_note-10">[10]</a> The longest-lived and most abundant (nearly 100%) naturally occurring <a href="/wiki/Isotope" title="Isotope">isotope</a> of protactinium, protactinium-231, has a <a href="/wiki/Half-life" title="Half-life">half-life</a> of 32,760 years and is a decay product of <a href="/wiki/Uranium-235" title="Uranium-235">uranium-235</a>. Much smaller trace amounts of the short-lived protactinium-234 and its <a href="/wiki/Nuclear_isomer" title="Nuclear isomer">nuclear isomer</a> protactinium-234m occur in the decay chain of <a href="/wiki/Uranium-238" title="Uranium-238">uranium-238</a>. Protactinium-233 occurs as a result of the decay of <a href="/wiki/Thorium" title="Thorium">thorium</a>-233 as part of the chain of events necessary to produce <a href="/wiki/Uranium-233" title="Uranium-233">uranium-233</a> by neutron irradiation of thorium-232. It is an undesired intermediate product in <a href="/wiki/Thorium-based_nuclear_power" title="Thorium-based nuclear power"> thorium-based</a> <a href="/wiki/Nuclear_reactor" title="Nuclear reactor">nuclear reactors</a>, and is therefore removed from the active zone of the reactor during the breeding process. Ocean science utilizes the element to understand the ancient ocean's geography. Analysis of the relative concentrations of various uranium, thorium, and protactinium isotopes in water and minerals is used in <a href="/wiki/Radiometric_dating" title="Radiometric dating">radiometric dating</a> of <a href="/wiki/Sediment" title="Sediment">sediments</a> up to 175,000 years old, and in modeling of various geological processes.<a href="#cite_note-11">[11]</a> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=1" title="Edit section: History">edit</a>]</div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Periodensystem_Mendelejews.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Periodensystem_Mendelejews.jpg/330px-Periodensystem_Mendelejews.jpg" decoding="async" width="330" height="151" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Periodensystem_Mendelejews.jpg/495px-Periodensystem_Mendelejews.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/74/Periodensystem_Mendelejews.jpg/660px-Periodensystem_Mendelejews.jpg 2x" data-file-width="709" data-file-height="325" /></a><figcaption><a href="/wiki/Dmitri_Mendeleev" title="Dmitri Mendeleev">Dmitri Mendeleev</a>'s 1871 periodic table with a gap for protactinium on the bottom row of the chart, between thorium and uranium</figcaption></figure> In 1871, <a href="/wiki/Dmitri_Mendeleev" title="Dmitri Mendeleev">Dmitri Mendeleev</a> <a href="/wiki/Mendeleev%27s_predicted_elements" title="Mendeleev's predicted elements">predicted</a> the existence of an element between <a href="/wiki/Thorium" title="Thorium">thorium</a> and <a href="/wiki/Uranium" title="Uranium">uranium</a>.<a href="#cite_note-Emsley-12">[12]</a> The actinide series was unknown at the time, so Mendeleev positioned <a href="/wiki/Uranium" title="Uranium">uranium</a> below <a href="/wiki/Tungsten" title="Tungsten">tungsten</a> in <a href="/wiki/Group_(periodic_table)" title="Group (periodic table)"> group</a> VI, and thorium below <a href="/wiki/Zirconium" title="Zirconium">zirconium</a> in group IV, leaving the space below <a href="/wiki/Tantalum" title="Tantalum">tantalum</a> in group V empty. Until the general acceptance of the <a href="/wiki/Actinide_concept" title="Actinide concept">actinide concept</a> in the late 1940s, <a href="/wiki/Periodic_table" title="Periodic table">periodic tables</a> were published with this structure.<a href="#cite_note-13">[13]</a> For a long time, chemists searched for <a href="/wiki/Mendeleev%27s_predicted_elements" title="Mendeleev's predicted elements">eka</a>-tantalum<a href="#cite_note-14">[note 1]</a> as an element with similar chemical properties to tantalum, making a discovery of protactinium nearly impossible. Tantalum's heavier analogue was later found to be the transuranic element <a href="/wiki/Dubnium" title="Dubnium">dubnium</a> – although dubnium is more chemically similar to protactinium, not tantalum.<a href="#cite_note-Fessl-15">[14]</a> In 1900, <a href="/wiki/William_Crookes" title="William Crookes">William Crookes</a> isolated protactinium as an intensely radioactive material from uranium; however, he could not characterize it as a new chemical element and thus named it uranium X (UX).<a href="#cite_note-Emsley-12">[12]</a><a href="#cite_note-google-16">[15]</a><a href="#cite_note-17">[16]</a> Crookes dissolved <a href="/wiki/Uranium_nitrate" class="mw-redirect" title="Uranium nitrate">uranium nitrate</a> in <a href="/wiki/Diethyl_ether" title="Diethyl ether">ether</a>, and the residual aqueous phase contained most of the 234 90Th and 234 91Pa . His method was used into the 1950s to isolate 234 90Th and 234 91Pa from uranium compounds.<a href="#cite_note-18">[17]</a> Protactinium was first identified in 1913, when <a href="/wiki/Kasimir_Fajans" class="mw-redirect" title="Kasimir Fajans">Kasimir Fajans</a> and <a href="/wiki/Oswald_Helmuth_G%C3%B6hring" title="Oswald Helmuth Göhring">Oswald Helmuth Göhring</a> encountered the isotope 234mPa during their studies of the decay chains of <a href="/wiki/Uranium-238" title="Uranium-238">uranium-238</a>: 238 92U → 234 90Th → 234m 91Pa → 234 92U . They named the new element "<a href="/wiki/Brevium" class="mw-redirect" title="Brevium">brevium</a>" (from the Latin word brevis, meaning brief or short) because of the short half-life of 1.16 minutes for 234m 91Pa (uranium X2).<a href="#cite_note-g1250-19">[18]</a><a href="#cite_note-g1254-20">[19]</a><a href="#cite_note-21">[20]</a><a href="#cite_note-22">[21]</a><a href="#cite_note-Scerri-23">[22]</a><a href="#cite_note-PaIsoDisc-24">[23]</a> In 1917–18, two groups of scientists, <a href="/wiki/Lise_Meitner" title="Lise Meitner">Lise Meitner</a> in collaboration with <a href="/wiki/Otto_Hahn" title="Otto Hahn">Otto Hahn</a> of <a href="/wiki/Germany" title="Germany">Germany</a> and <a href="/wiki/Frederick_Soddy" title="Frederick Soddy">Frederick Soddy</a> and John Cranston of <a href="/wiki/Great_Britain" title="Great Britain">Great Britain</a>, independently discovered another isotope, 231Pa, having a much longer half-life of 32,760 years.<a href="#cite_note-meitner-8">[8]</a><a href="#cite_note-Scerri-23">[22]</a><a href="#cite_note-25">[24]</a> Meitner changed the name "brevium" to protactinium as the new element was part of the decay chain of uranium-235 as the parent of actinium (from the <a href="/wiki/Greek_language" title="Greek language">Greek</a>: πρῶτος prôtos, meaning "first, before").<a href="#cite_note-26">[25]</a> The <a href="/wiki/International_Union_of_Pure_and_Applied_Chemistry" title="International Union of Pure and Applied Chemistry">IUPAC</a> confirmed this naming in 1949.<a href="#cite_note-CRC-27">[26]</a><a href="#cite_note-g1251-28">[27]</a> The discovery of protactinium completed one of the last gaps in early versions of the periodic table, and brought fame to the involved scientists.<a href="#cite_note-29">[28]</a> <a href="/wiki/Aristid_von_Grosse" title="Aristid von Grosse">Aristid von Grosse</a> produced 2 milligrams of Pa2O5 in 1927,<a href="#cite_note-30">[29]</a> and in 1934 first isolated elemental protactinium from 0.1 milligrams of Pa2O5.<a href="#cite_note-31">[30]</a> He used two different procedures: in the first, protactinium oxide was irradiated by 35 keV electrons in vacuum. In the other, called the <a href="/wiki/Crystal_bar_process" class="mw-redirect" title="Crystal bar process">van Arkel–de Boer process</a>, the oxide was chemically converted to a <a href="/wiki/Halide" title="Halide">halide</a> (<a href="/wiki/Chloride" title="Chloride">chloride</a>, <a href="/wiki/Bromide" title="Bromide">bromide</a> or <a href="/wiki/Iodide" title="Iodide">iodide</a>) and then reduced in a vacuum with an electrically heated metallic filament:<a href="#cite_note-CRC-27">[26]</a><a href="#cite_note-32">[31]</a> <dl><dd>2 PaI5 → 2 Pa + 5 I2</dd></dl> In 1961, the <a href="/wiki/United_Kingdom_Atomic_Energy_Authority" title="United Kingdom Atomic Energy Authority">United Kingdom Atomic Energy Authority</a> (UKAEA) produced 127 grams of 99.9% pure protactinium-231 by processing 60 tonnes of waste material in a 12-stage process, at a cost of about US$500,000.<a href="#cite_note-CRC-27">[26]</a><a href="#cite_note-Myasoedov-33">[32]</a> For many years, this was the world's only significant supply of protactinium, which was provided to various laboratories for scientific studies.<a href="#cite_note-Emsley-12">[12]</a> The <a href="/wiki/Oak_Ridge_National_Laboratory" title="Oak Ridge National Laboratory">Oak Ridge National Laboratory</a> in the US provided protactinium at a cost of about US$280/gram.<a href="#cite_note-34">[33]</a> <div class="mw-heading mw-heading2"><h2 id="Isotopes">Isotopes</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=2" title="Edit section: Isotopes">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Isotopes_of_protactinium" title="Isotopes of protactinium">Isotopes of protactinium</a></div> Twenty-nine <a href="/wiki/Radioisotope" class="mw-redirect" title="Radioisotope">radioisotopes</a> of protactinium have been discovered. The most stable are 231Pa with a half-life of 32,760 years, 233Pa with a half-life of 27 days, and 230Pa with a half-life of 17.4 days. All other isotopes have half-lives shorter than 1.6 days, and the majority of these have half-lives less than 1.8 seconds. Protactinium also has two <a href="/wiki/Nuclear_isomer" title="Nuclear isomer">nuclear isomers</a>, 217mPa (half-life 1.2 milliseconds) and 234mPa (half-life 1.16 minutes).<a href="#cite_note-nubase-35">[34]</a> The primary <a href="/wiki/Decay_mode" class="mw-redirect" title="Decay mode">decay mode</a> for the most stable isotope 231Pa and lighter (211Pa to 231Pa) is <a href="/wiki/Alpha_decay" title="Alpha decay">alpha decay</a>, producing <a href="/wiki/Isotopes_of_actinium" title="Isotopes of actinium">isotopes of actinium</a>. The primary mode for the heavier isotopes (232Pa to 239Pa) is <a href="/wiki/Beta_decay" title="Beta decay">beta decay</a>, producing <a href="/wiki/Isotopes_of_uranium" title="Isotopes of uranium">isotopes of uranium</a>.<a href="#cite_note-nubase-35">[34]</a> <div class="mw-heading mw-heading3"><h3 id="Nuclear_fission">Nuclear fission</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=3" title="Edit section: Nuclear fission">edit</a>]</div> The longest-lived and most abundant isotope, 231Pa, can fission from <a href="/wiki/Neutron_temperature#Fast" title="Neutron temperature">fast neutrons</a> exceeding ~1 MeV.<a href="#cite_note-AVG231-36">[35]</a> 233Pa, the other isotope of protactinium produced in nuclear reactors, also has a fission threshold of 1 MeV.<a href="#cite_note-37">[36]</a> <div class="mw-heading mw-heading2"><h2 id="Occurrence">Occurrence</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=4" title="Edit section: Occurrence">edit</a>]</div> Protactinium is one of the rarest and most expensive naturally occurring elements. It is found in the form of two isotopes – 231Pa and 234Pa, with the isotope 234Pa occurring in two different energy states. Nearly all natural protactinium is protactinium-231. It is an <a href="/wiki/Alpha_particle" title="Alpha particle">alpha emitter</a> and is formed by the decay of uranium-235, whereas the <a href="/wiki/Beta_particle" title="Beta particle">beta radiating</a> protactinium-234 is produced as a result of <a href="/wiki/File:Decay_chain(4n%2B2,_Uranium_series).PNG" title="File:Decay chain(4n+2, Uranium series).PNG">uranium-238 decay</a>. Nearly all uranium-238 (99.8%) decays first to the shorter-lived 234mPa isomer.<a href="#cite_note-ANL-38">[37]</a> Protactinium occurs in <a href="/wiki/Uraninite" title="Uraninite">uraninite</a> (pitchblende) at concentrations of about 0.3-3 <a href="/wiki/Parts-per_notation" title="Parts-per notation">parts</a> 231Pa per million parts (ppm) of ore.<a href="#cite_note-Emsley-12">[12]</a> Whereas the usual content is closer to 0.3 ppm<a href="#cite_note-brit-39">[38]</a> (e.g. in <a href="/wiki/J%C3%A1chymov" title="Jáchymov">Jáchymov</a>, <a href="/wiki/Czech_Republic" title="Czech Republic">Czech Republic</a><a href="#cite_note-40">[39]</a>), some ores from the <a href="/wiki/Democratic_Republic_of_the_Congo" title="Democratic Republic of the Congo">Democratic Republic of the Congo</a> have about 3 ppm.<a href="#cite_note-CRC-27">[26]</a> Protactinium is homogeneously dispersed in most natural materials and in water, but at much lower concentrations on the order of one part per trillion, corresponding to a radioactivity of 0.1 picocuries (pCi)/g. There is about 500 times more protactinium in sandy soil particles than in water, even when compared to water present in the same sample of soil. Much higher ratios of 2,000 and above are measured in <a href="/wiki/Loam" title="Loam">loam</a> soils and clays, such as <a href="/wiki/Bentonite" title="Bentonite">bentonite</a>.<a href="#cite_note-ANL-38">[37]</a><a href="#cite_note-41">[40]</a> <div class="mw-heading mw-heading3"><h3 id="In_nuclear_reactors">In nuclear reactors</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=5" title="Edit section: In nuclear reactors">edit</a>]</div> Two major protactinium isotopes, 231Pa and 233Pa, are produced from thorium in <a href="/wiki/Nuclear_reactor" title="Nuclear reactor">nuclear reactors</a>; both are undesirable and are usually removed, thereby adding complexity to the reactor design and operation. In particular, 232Th, via <a href="/wiki/Nuclear_reaction#Reactions_with_neutrons" title="Nuclear reaction"> (n, 2n)</a> reactions, produces 231Th, which quickly decays to 231Pa (half-life 25.5 hours). The last isotope, while not a transuranic waste, has a long half-life of 32,760 years, and is a major contributor to the long-term <a href="/wiki/Radiotoxic" class="mw-redirect" title="Radiotoxic">radiotoxicity</a> of spent nuclear fuel.<a href="#cite_note-b1-42">[41]</a> Protactinium-233 is formed upon neutron capture by 232Th. It either further decays to uranium-233, or captures another neutron and converts into the non-fissile uranium-234.<a href="#cite_note-43">[42]</a> 233Pa has a relatively long half-life of 27 days and high <a href="/wiki/Cross_section_(physics)" title="Cross section (physics)">cross section</a> for neutron capture (the so-called "<a href="/wiki/Neutron_poison" title="Neutron poison">neutron poison</a>"). Thus, instead of rapidly decaying to the useful 233U, a significant fraction of 233Pa converts to non-fissile isotopes and consumes neutrons, degrading <a href="/wiki/Neutron_economy" title="Neutron economy">reactor efficiency</a>. To limit the loss of neutrons, 233Pa is extracted from the active zone of thorium <a href="/wiki/Molten_salt_reactor" class="mw-redirect" title="Molten salt reactor">molten salt reactors</a> during their operation, so that it can only decay into 233U. Extraction of 233Pa is achieved using columns of molten <a href="/wiki/Bismuth" title="Bismuth">bismuth</a> with lithium dissolved in it. In short, lithium selectively reduces protactinium salts to protactinium metal, which is then extracted from the molten-salt cycle, while the molten bismuth is merely a carrier, selected due to its low <a href="/wiki/Melting_point" title="Melting point">melting point</a> of 271 °C, low vapor pressure, good solubility for lithium and actinides, and <a href="/wiki/Miscibility" title="Miscibility"> immiscibility</a> with molten <a href="/wiki/Halide" title="Halide">halides</a>.<a href="#cite_note-b1-42">[41]</a> <div class="mw-heading mw-heading2"><h2 id="Preparation">Preparation</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=6" title="Edit section: Preparation">edit</a>]</div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Uraninite-39029.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Uraninite-39029.jpg/170px-Uraninite-39029.jpg" decoding="async" width="170" height="268" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Uraninite-39029.jpg/255px-Uraninite-39029.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Uraninite-39029.jpg/340px-Uraninite-39029.jpg 2x" data-file-width="507" data-file-height="799" /></a><figcaption>Protactinium occurs in <a href="/wiki/Uraninite" title="Uraninite">uraninite</a> ores.</figcaption></figure> Before the advent of nuclear reactors, protactinium was separated for scientific experiments from uranium ores. Since reactors have become more common, it is mostly produced as an intermediate product of <a href="/wiki/Nuclear_fission" title="Nuclear fission">nuclear fission</a> in <a href="/wiki/Thorium_fuel_cycle" title="Thorium fuel cycle">thorium fuel cycle</a> reactors as an intermediate in the production of the fissile uranium-233: <dl><dd><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {^{232}_{90}Th + ^{1}_{0}n -> ^{233}_{90}Th ->[\beta^-][22.3\ {\ce {min}}] ^{233}_{91}Pa ->[\beta^-][26.967\ {\ce {d}}] ^{233}_{92}U.}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mmultiscripts> <mtext>Th</mtext> <none /> <none /> <mprescripts /> <mn>90</mn> <mn>232</mn> </mmultiscripts> <mo>+</mo> <mmultiscripts> <mtext>n</mtext> <none /> <none /> <mprescripts /> <mn>0</mn> <mn>1</mn> </mmultiscripts> <mo stretchy="false">⟶</mo> <mmultiscripts> <mtext>Th</mtext> <none /> <none /> <mprescripts /> <mn>90</mn> <mn>233</mn> </mmultiscripts> <mrow class="MJX-TeXAtom-REL"> <munderover> <mo>→</mo> <mpadded width="+0.611em" lspace="0.278em" voffset="-.24em"> <mn>22.3</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mtext>min</mtext> </mrow> </mpadded> <mpadded width="+0.611em" lspace="0.278em" voffset=".15em"> <msup> <mi>β</mi> <mo>−</mo> </msup> </mpadded> </munderover> </mrow> <mmultiscripts> <mtext>Pa</mtext> <none /> <none /> <mprescripts /> <mn>91</mn> <mn>233</mn> </mmultiscripts> <mrow class="MJX-TeXAtom-REL"> <munderover> <mo>→</mo> <mpadded width="+0.611em" lspace="0.278em" voffset="-.24em"> <mn>26.967</mn> <mtext> </mtext> <mrow class="MJX-TeXAtom-ORD"> <mtext>d</mtext> </mrow> </mpadded> <mpadded width="+0.611em" lspace="0.278em" voffset=".15em"> <msup> <mi>β</mi> <mo>−</mo> </msup> </mpadded> </munderover> </mrow> <mmultiscripts> <mtext>U</mtext> <none /> <none /> <mprescripts /> <mn>92</mn> <mn>233</mn> </mmultiscripts> <mo>⋅</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\ce {^{232}_{90}Th + ^{1}_{0}n -> ^{233}_{90}Th ->[\beta^-][22.3\ {\ce {min}}] ^{233}_{91}Pa ->[\beta^-][26.967\ {\ce {d}}] ^{233}_{92}U.}}}</annotation> </semantics> </math><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/04109ed78dd8a9872b2bc71a09a18761cdd5d870" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.828ex; margin-top: -0.415ex; margin-bottom: -0.51ex; width:49.396ex; height:6.176ex;" alt="{\displaystyle {\ce {^{232}_{90}Th + ^{1}_{0}n -> ^{233}_{90}Th ->[\beta^-][22.3\ {\ce {min}}] ^{233}_{91}Pa ->[\beta^-][26.967\ {\ce {d}}] ^{233}_{92}U.}}}"></dd></dl> The isotope 231Pa can be prepared by irradiating thorium-230 with <a href="/wiki/Neutron_temperature#Cold_(slow)_neutrons" title="Neutron temperature"> slow neutrons</a>, converting it to the beta-decaying thorium-231; or, by irradiating thorium-232 with fast neutrons, generating thorium-231 and 2 neutrons. Protactinium metal can be prepared by reduction of its <a href="/wiki/Fluoride" title="Fluoride">fluoride</a> with <a href="/wiki/Calcium" title="Calcium">calcium</a>,<a href="#cite_note-exp-44">[43]</a> <a href="/wiki/Lithium" title="Lithium">lithium</a>, or <a href="/wiki/Barium" title="Barium">barium</a> at a temperature of 1300–1400 °C.<a href="#cite_note-super-45">[44]</a><a href="#cite_note-pao2-46">[45]</a> <div class="mw-heading mw-heading2"><h2 id="Properties">Properties</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=7" title="Edit section: Properties">edit</a>]</div> Protactinium is an <a href="/wiki/Actinide" title="Actinide">actinide</a> positioned in the <a href="/wiki/Periodic_table" title="Periodic table">periodic table</a> to the left of <a href="/wiki/Uranium" title="Uranium">uranium</a> and to the right of <a href="/wiki/Thorium" title="Thorium">thorium</a>, and many of its physical properties are intermediate between its neighboring actinides. Protactinium is denser and more rigid than thorium, but is lighter than uranium; its melting point is lower than that of thorium, but higher than that of uranium. The thermal expansion, electrical, and thermal conductivities of these three elements are comparable and are typical of <a href="/wiki/Post-transition_metal" title="Post-transition metal">post-transition metals</a>. The estimated <a href="/wiki/Shear_modulus" title="Shear modulus">shear modulus</a> of protactinium is similar to that of <a href="/wiki/Titanium" title="Titanium">titanium</a>.<a href="#cite_note-47">[46]</a> Protactinium is a metal with silvery-gray luster that is preserved for some time in air.<a href="#cite_note-CRC-27">[26]</a><a href="#cite_note-Myasoedov-33">[32]</a> Protactinium easily reacts with oxygen, water vapor, and acids, but not with alkalis.<a href="#cite_note-Emsley-12">[12]</a> At room temperature, protactinium crystallizes in the body-centered <a href="/wiki/Tetragonal_crystal_system" title="Tetragonal crystal system">tetragonal</a> structure, which can be regarded as distorted body-centered cubic lattice; this structure does not change upon compression up to 53 GPa. The structure changes to face-centered cubic (fcc) upon cooling from high temperature, at about 1200 °C.<a href="#cite_note-exp-44">[43]</a><a href="#cite_note-48">[47]</a> The thermal expansion coefficient of the tetragonal phase between room temperature and 700 °C is 9.9×10−6/°C.<a href="#cite_note-exp-44">[43]</a> Protactinium is <a href="/wiki/Paramagnetism" title="Paramagnetism">paramagnetic</a> and no magnetic transitions are known for it at any temperature.<a href="#cite_note-49">[48]</a> It becomes <a href="/wiki/Superconductivity" title="Superconductivity">superconductive</a> at temperatures below 1.4 K.<a href="#cite_note-Emsley-12">[12]</a><a href="#cite_note-super-45">[44]</a> Protactinium tetrachloride is paramagnetic at room temperature, but becomes <a href="/wiki/Ferromagnetism" title="Ferromagnetism">ferromagnetic</a> when cooled to 182 K.<a href="#cite_note-50">[49]</a> Protactinium exists in two major <a href="/wiki/Oxidation_state" title="Oxidation state">oxidation states</a>: +4 and +5, both in solids and solutions; and the +3 and +2 states, which have been observed in some solids. As the electron configuration of the neutral atom is [Rn]5f26d17s2, the +5 oxidation state corresponds to the low-energy (and thus favored) 5f0 configuration. Both +4 and +5 states easily form <a href="/wiki/Hydroxide" title="Hydroxide">hydroxides</a> in water, with the predominant ions being Pa(OH)3+, <style data-mw-deduplicate="TemplateStyles:r1123817410">.mw-parser-output .template-chem2-su{display:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em}.mw-parser-output .template-chem2-su>span{display:block;text-align:left}.mw-parser-output sub.template-chem2-sub{font-size:80%;vertical-align:-0.35em}.mw-parser-output sup.template-chem2-sup{font-size:80%;vertical-align:0.65em}</style>Pa(OH)2+2, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">Pa(OH)+3, and Pa(OH)4, all of which are colorless.<a href="#cite_note-g1265-51">[50]</a> Other known protactinium ions include <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaCl2+2, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaSO2+4, PaF3+, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaF2+2, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaF−6, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaF2−7, and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410">PaF3−8.<a href="#cite_note-g1275-52">[51]</a><a href="#cite_note-trif-53">[52]</a> <div class="mw-heading mw-heading2"><h2 id="Chemical_compounds">Chemical compounds</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=8" title="Edit section: Chemical compounds">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Protactinium_compounds" title="Protactinium compounds">Protactinium compounds</a></div> <table class="wikitable" style="text-align: center"> <tbody><tr> <th>Formula </th> <th>color </th> <th>symmetry </th> <th><a href="/wiki/Space_group" title="Space group">space group</a> </th> <th>No </th> <th><a href="/wiki/Pearson_symbol" title="Pearson symbol">Pearson symbol</a> </th> <th>a (pm) </th> <th>b (pm) </th> <th>c (pm) </th> <th>Z </th> <th>density (g/cm3) </th></tr> <tr> <td>Pa </td> <td>silvery-gray </td> <td><a href="/wiki/Tetragonal_crystal_system" title="Tetragonal crystal system">tetragonal</a><a href="#cite_note-str-5">[5]</a> </td> <td>I4/mmm </td> <td>139 </td> <td>tI2 </td> <td>392.5 </td> <td>392.5 </td> <td>323.8 </td> <td>2 </td> <td>15.37 </td></tr> <tr> <td>PaO </td> <td> </td> <td>rocksalt<a href="#cite_note-pao2-46">[45]</a> </td> <td>Fm3m </td> <td>225 </td> <td>cF8 </td> <td>496.1 </td> <td> </td> <td> </td> <td>4 </td> <td>13.44 </td></tr> <tr> <td><a href="/wiki/Protactinium(IV)_oxide" title="Protactinium(IV) oxide">PaO2</a> </td> <td>black </td> <td>fcc<a href="#cite_note-pao2-46">[45]</a> </td> <td>Fm3m </td> <td>225 </td> <td>cF12 </td> <td>550.5 </td> <td> </td> <td> </td> <td>4 </td> <td>10.47 </td></tr> <tr> <td><a href="/wiki/Protactinium(V)_oxide" title="Protactinium(V) oxide">Pa2O5</a> </td> <td>white </td> <td> </td> <td>Fm3m<a href="#cite_note-pao2-46">[45]</a> </td> <td>225 </td> <td>cF16 </td> <td>547.6 </td> <td>547.6 </td> <td>547.6 </td> <td>4 </td> <td>10.96 </td></tr> <tr> <td>Pa2O5 </td> <td>white </td> <td>orthorhombic<a href="#cite_note-pao2-46">[45]</a> </td> <td> </td> <td> </td> <td> </td> <td>692 </td> <td>402 </td> <td>418 </td> <td> </td> <td> </td></tr> <tr> <td>PaH3 </td> <td>black </td> <td>cubic<a href="#cite_note-pao2-46">[45]</a> </td> <td>Pm3n </td> <td>223 </td> <td>cP32 </td> <td>664.8 </td> <td>664.8 </td> <td>664.8 </td> <td>8 </td> <td>10.58 </td></tr> <tr> <td>PaF4 </td> <td>brown-red </td> <td>monoclinic<a href="#cite_note-pao2-46">[45]</a> </td> <td>C2/c </td> <td>15 </td> <td>mS60 </td> <td> </td> <td> </td> <td> </td> <td>2 </td> <td> </td></tr> <tr> <td>PaCl4 </td> <td>green-yellow </td> <td><a href="/wiki/Tetragonal_crystal_system" title="Tetragonal crystal system">tetragonal</a><a href="#cite_note-54">[53]</a> </td> <td>I41/amd </td> <td>141 </td> <td>tI20 </td> <td>837.7 </td> <td>837.7 </td> <td>748.1 </td> <td>4 </td> <td>4.72 </td></tr> <tr> <td>PaBr4 </td> <td>brown </td> <td>tetragonal<a href="#cite_note-pabr4-55">[54]</a><a href="#cite_note-pabr5b-56">[55]</a> </td> <td>I41/amd </td> <td>141 </td> <td>tI20 </td> <td>882.4 </td> <td>882.4 </td> <td>795.7 </td> <td> </td> <td> </td></tr> <tr> <td><a href="/wiki/Protactinium(V)_chloride" title="Protactinium(V) chloride">PaCl5</a> </td> <td>yellow </td> <td><a href="/wiki/Monoclinic_crystal_system" title="Monoclinic crystal system">monoclinic</a><a href="#cite_note-pacl5-57">[56]</a> </td> <td>C2/c </td> <td>15 </td> <td>mS24 </td> <td>797 </td> <td>1135 </td> <td>836 </td> <td>4 </td> <td>3.74 </td></tr> <tr> <td>PaBr5 </td> <td>red </td> <td>monoclinic<a href="#cite_note-pabr5b-56">[55]</a><a href="#cite_note-pabr5-58">[57]</a> </td> <td>P21/c </td> <td>14 </td> <td>mP24 </td> <td>838.5 </td> <td>1120.5 </td> <td>1214.6 </td> <td>4 </td> <td>4.98 </td></tr> <tr> <td>PaOBr3 </td> <td> </td> <td>monoclinic<a href="#cite_note-pabr5b-56">[55]</a> </td> <td>C2 </td> <td> </td> <td> </td> <td>1691.1 </td> <td>387.1 </td> <td>933.4 </td> <td> </td> <td> </td></tr> <tr> <td>Pa(PO3)4 </td> <td> </td> <td>orthorhombic<a href="#cite_note-papo3-59">[58]</a> </td> <td> </td> <td> </td> <td> </td> <td>696.9 </td> <td>895.9 </td> <td>1500.9 </td> <td> </td> <td> </td></tr> <tr> <td>Pa2P2O7 </td> <td> </td> <td>cubic<a href="#cite_note-papo3-59">[58]</a> </td> <td>Pa3 </td> <td> </td> <td> </td> <td>865 </td> <td>865 </td> <td>865 </td> <td> </td> <td> </td></tr> <tr> <td>Pa(C8H8)2 </td> <td>golden-yellow </td> <td>monoclinic<a href="#cite_note-cene-60">[59]</a> </td> <td> </td> <td> </td> <td> </td> <td>709 </td> <td>875 </td> <td>1062 </td> <td> </td> <td> </td></tr></tbody></table> Here, a, b, and c are lattice constants in picometers, No is the space group number, and Z is the number of <a href="/wiki/Formula_unit" title="Formula unit">formula units</a> per <a href="/wiki/Unit_cell" title="Unit cell">unit cell</a>; fcc stands for the <a href="/wiki/Cubic_crystal_system" title="Cubic crystal system">face-centered cubic</a> symmetry. Density was not measured directly but calculated from the lattice parameters. <div class="mw-heading mw-heading3"><h3 id="Oxides_and_oxygen-containing_salts">Oxides and oxygen-containing salts</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=9" title="Edit section: Oxides and oxygen-containing salts">edit</a>]</div> Protactinium oxides are known for the metal oxidation states +2, +4, and +5. The most stable is the white pentoxide <a href="/wiki/Protactinium(V)_oxide" title="Protactinium(V) oxide">Pa2O5</a>, which can be produced by igniting protactinium(V) hydroxide in <a href="/wiki/Air" class="mw-redirect" title="Air">air</a> at a temperature of 500 °C.<a href="#cite_note-g1268-61">[60]</a> Its crystal structure is cubic, and the chemical composition is often non-stoichiometric, described as PaO2.25. Another phase of this oxide with orthorhombic symmetry has also been reported.<a href="#cite_note-pao2-46">[45]</a><a href="#cite_note-pacl4b-62">[61]</a> The black dioxide <a href="/wiki/Protactinium(IV)_oxide" title="Protactinium(IV) oxide">PaO2</a> is obtained from the pentoxide by reducing it at 1550 °C with hydrogen. It is not readily soluble in either dilute or concentrated <a href="/wiki/Nitric_acid" title="Nitric acid">nitric</a>, <a href="/wiki/Hydrochloric_acid" title="Hydrochloric acid">hydrochloric</a>, or <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a>, but easily dissolves in <a href="/wiki/Hydrofluoric_acid" title="Hydrofluoric acid">hydrofluoric acid</a>.<a href="#cite_note-pao2-46">[45]</a> The dioxide can be converted back to pentoxide by heating in oxygen-containing atmosphere to 1100 °C.<a href="#cite_note-pacl4b-62">[61]</a> The monoxide PaO has only been observed as a thin coating on protactinium metal, but not in an isolated bulk form.<a href="#cite_note-pao2-46">[45]</a> Protactinium forms mixed binary oxides with various metals. With alkali metals A, the crystals have a chemical formula APaO3 and <a href="/wiki/Perovskite_structure" class="mw-redirect" title="Perovskite structure">perovskite structure</a>; A3PaO4 and distorted rock-salt structure; or A7PaO6, where oxygen atoms form a hexagonal close-packed lattice. In all of these materials, the protactinium ions are octahedrally coordinated.<a href="#cite_note-g1269-63">[62]</a><a href="#cite_note-64">[63]</a> The pentoxide Pa2O5 combines with rare-earth metal oxides R2O3 to form various nonstoichiometric mixed-oxides, also of perovskite structure.<a href="#cite_note-65">[64]</a> Protactinium oxides are <a href="/wiki/Basic_oxide" title="Basic oxide">basic</a>; they easily convert to hydroxides and can form various salts, such as <a href="/wiki/Sulfate" title="Sulfate">sulfates</a>, <a href="/wiki/Phosphate" title="Phosphate">phosphates</a>, <a href="/wiki/Nitrate" title="Nitrate">nitrates</a>, etc. The nitrate is usually white but can be brown due to <a href="/wiki/Radiolysis" title="Radiolysis">radiolytic</a> decomposition. Heating the nitrate in air at 400 °C converts it to the white protactinium pentoxide.<a href="#cite_note-target-66">[65]</a> The polytrioxophosphate Pa(PO3)4 can be produced by reacting the difluoride sulfate PaF2SO4 with <a href="/wiki/Phosphoric_acid" title="Phosphoric acid">phosphoric acid</a> (H3PO4) under an inert atmosphere. Heating the product to about 900 °C eliminates the reaction by-products, which include <a href="/wiki/Hydrofluoric_acid" title="Hydrofluoric acid">hydrofluoric acid</a>, <a href="/wiki/Sulfur_trioxide" title="Sulfur trioxide">sulfur trioxide</a>, and phosphoric anhydride. Heating it to higher temperatures in an inert atmosphere decomposes Pa(PO3)4 into the diphosphate PaP2O7, which is analogous to diphosphates of other actinides. In the diphosphate, the PO3 groups form pyramids of C2v symmetry. Heating PaP2O7 in air to 1400 °C decomposes it into the pentoxides of phosphorus and protactinium.<a href="#cite_note-papo3-59">[58]</a> <div class="mw-heading mw-heading3"><h3 id="Halides">Halides</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=10" title="Edit section: Halides">edit</a>]</div> Protactinium(V) fluoride forms white crystals where protactinium ions are arranged in pentagonal bipyramids and <a href="/wiki/Coordination_number" title="Coordination number">coordinated</a> by 7 other ions. The coordination is the same in protactinium(V) chloride, but the color is yellow. The coordination changes to octahedral in the brown protactinium(V) bromide, but is unknown for protactinium(V) iodide. The protactinium coordination in all its tetrahalides is 8, but the arrangement is square antiprismatic in protactinium(IV) fluoride and dodecahedral in the chloride and bromide. Brown-colored protactinium(III) iodide has been reported, where protactinium ions are 8-coordinated in a bicapped trigonal prismatic arrangement.<a href="#cite_note-g1270-67">[66]</a> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:PaCl5.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/PaCl5.svg/220px-PaCl5.svg.png" decoding="async" width="220" height="79" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/PaCl5.svg/330px-PaCl5.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/dd/PaCl5.svg/440px-PaCl5.svg.png 2x" data-file-width="635" data-file-height="227" /></a><figcaption>Coordination of protactinium (solid circles) and halogen atoms (open circles) in protactinium(V) fluoride or chloride.</figcaption></figure> Protactinium(V) fluoride and protactinium(V) chloride have a polymeric structure of monoclinic symmetry. There, within one polymeric chain, all halide atoms lie in one graphite-like plane and form planar pentagons around the protactinium ions. The 7-coordination of protactinium originates from the five halide atoms and two bonds to protactinium atoms belonging to the nearby chains. These compounds easily hydrolyze in water.<a href="#cite_note-g1271-68">[67]</a> The pentachloride melts at 300 °C and sublimates at even lower temperatures. Protactinium(V) fluoride can be prepared by reacting protactinium oxide with either <a href="/wiki/Bromine_pentafluoride" title="Bromine pentafluoride">bromine pentafluoride</a> or <a href="/wiki/Bromine_trifluoride" title="Bromine trifluoride">bromine trifluoride</a> at about 600 °C, and protactinium(IV) fluoride is obtained from the oxide and a mixture of hydrogen and <a href="/wiki/Hydrogen_fluoride" title="Hydrogen fluoride">hydrogen fluoride</a> at 600 °C; a large excess of hydrogen is required to remove atmospheric oxygen leaks into the reaction.<a href="#cite_note-pao2-46">[45]</a> Protactinium(V) chloride is prepared by reacting protactinium oxide with <a href="/wiki/Carbon_tetrachloride" title="Carbon tetrachloride">carbon tetrachloride</a> at temperatures of 200–300 °C.<a href="#cite_note-pao2-46">[45]</a> The by-products (such as PaOCl3) are removed by fractional sublimation.<a href="#cite_note-pacl5-57">[56]</a> Reduction of protactinium(V) chloride with hydrogen at about 800 °C yields protactinium(IV) chloride – a yellow-green solid that sublimes in vacuum at 400 °C. It can also be obtained directly from protactinium dioxide by treating it with carbon tetrachloride at 400 °C.<a href="#cite_note-pao2-46">[45]</a> Protactinium bromides are produced by the action of <a href="/wiki/Aluminium_bromide" title="Aluminium bromide">aluminium bromide</a>, <a href="/wiki/Hydrogen_bromide" title="Hydrogen bromide">hydrogen bromide</a>, <a href="/wiki/Carbon_tetrabromide" title="Carbon tetrabromide">carbon tetrabromide</a>, or a mixture of hydrogen bromide and <a href="/wiki/Thionyl_bromide" title="Thionyl bromide">thionyl bromide</a> on protactinium oxide. They can alternatively be produced by reacting protactinium pentachloride with hydrogen bromide or thionyl bromide.<a href="#cite_note-pao2-46">[45]</a> Protactinium(V) bromide has two similar monoclinic forms: one is obtained by sublimation at 400–410 °C, and another by sublimation at a slightly lower temperature of 390–400 °C.<a href="#cite_note-pabr5b-56">[55]</a><a href="#cite_note-pabr5-58">[57]</a> Protactinium iodides can be produced by reacting protactinium metal with elemental iodine at 600 °C, and by reacting Pa2O5 with AlO3 at 600 °C.<a href="#cite_note-pao2-46">[45]</a> Protactinium(III) iodide can be obtained by heating protactinium(V) iodide in vacuum.<a href="#cite_note-g1271-68">[67]</a> As with oxides, protactinium forms mixed halides with alkali metals. The most remarkable among these is Na3PaF8, where the protactinium ion is symmetrically surrounded by 8 F− ions, forming a nearly perfect cube.<a href="#cite_note-g1275-52">[51]</a> More complex protactinium fluorides are also known, such as Pa2F9<a href="#cite_note-g1271-68">[67]</a> and ternary fluorides of the types MPaF6 (M = Li, Na, K, Rb, Cs or NH4), M2PaF7 (M = K, Rb, Cs or NH4), and M3PaF8 (M = Li, Na, Rb, Cs), all of which are white crystalline solids. The MPaF6 formula can be represented as a combination of MF and PaF5. These compounds can be obtained by evaporating a hydrofluoric acid solution containing both complexes. For the small alkali cations like Na, the crystal structure is tetragonal, whereas it becomes orthorhombic for larger cations K+, Rb+, Cs+ or NH4+. A similar variation was observed for the M2PaF7 fluorides: namely, the crystal symmetry was dependent on the cation and differed for Cs2PaF7 and M2PaF7 (M = K, Rb or NH4).<a href="#cite_note-trif-53">[52]</a> <div class="mw-heading mw-heading3"><h3 id="Other_inorganic_compounds">Other inorganic compounds</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=11" title="Edit section: Other inorganic compounds">edit</a>]</div> Oxyhalides and oxysulfides of protactinium are known. PaOBr3 has a monoclinic structure composed of double-chain units where protactinium has coordination 7 and is arranged into pentagonal bipyramids. The chains are interconnected through oxygen and bromine atoms, and each oxygen atom is related to three protactinium atoms.<a href="#cite_note-pabr5b-56">[55]</a> PaOS is a light-yellow, non-volatile solid with a cubic crystal lattice isostructural to that of other actinide oxysulfides. It is obtained by reacting protactinium(V) chloride with a mixture of <a href="/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">hydrogen sulfide</a> and <a href="/wiki/Carbon_disulfide" title="Carbon disulfide">carbon disulfide</a> at 900 °C.<a href="#cite_note-pao2-46">[45]</a> In hydrides and nitrides, protactinium has a low oxidation state of about +3. The hydride is obtained by direct action of hydrogen on the metal at 250 °C, and the nitride is a product of ammonia and protactinium tetrachloride or pentachloride. This bright yellow solid is thermally stable to 800 °C in vacuum. Protactinium carbide (PaC) is formed by the reduction of protactinium tetrafluoride with barium in a carbon crucible at a temperature of about 1400 °C.<a href="#cite_note-pao2-46">[45]</a> Protactinium forms <a href="/wiki/Borohydride" title="Borohydride">borohydrides</a>, which include Pa(BH4)4. It has an unusual polymeric structure with helical chains, where the protactinium atom has coordination number of 12 and is surrounded by six BH4− ions.<a href="#cite_note-g1277-69">[68]</a> <div class="mw-heading mw-heading3"><h3 id="Organometallic_compounds">Organometallic compounds</h3>[<a href="/w/index.php?title=Protactinium&action=edit&section=12" title="Edit section: Organometallic compounds">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Uranocene-3D-balls.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Uranocene-3D-balls.png/170px-Uranocene-3D-balls.png" decoding="async" width="170" height="210" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Uranocene-3D-balls.png/255px-Uranocene-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Uranocene-3D-balls.png/340px-Uranocene-3D-balls.png 2x" data-file-width="891" data-file-height="1100" /></a><figcaption>The proposed structure of the protactinocene (Pa(C8H8)2) molecule</figcaption></figure> Protactinium(IV) forms a tetrahedral complex tetrakis(cyclopentadienyl)protactinium(IV) (or Pa(C5H5)4) with four <a href="/wiki/Cyclopentadienyl_complex" title="Cyclopentadienyl complex">cyclopentadienyl</a> rings, which can be synthesized by reacting protactinium(IV) chloride with molten Be(C5H5)2. One ring can be substituted with a halide atom.<a href="#cite_note-g1278-70">[69]</a> Another organometallic complex is the golden-yellow bis(π-cyclooctatetraene) protactinium, or <a href="/wiki/Protactinocene" class="mw-redirect" title="Protactinocene">protactinocene</a> (Pa(C8H8)2), which is analogous in structure to <a href="/wiki/Uranocene" title="Uranocene">uranocene</a>. There, the metal atom is sandwiched between two <a href="/wiki/Cyclooctatetraene" title="Cyclooctatetraene">cyclooctatetraene</a> ligands. Similar to uranocene, it can be prepared by reacting protactinium tetrachloride with dipotassium <a href="/wiki/Cyclooctatetraene" title="Cyclooctatetraene">cyclooctatetraenide</a> (K2C8H8) in <a href="/wiki/Tetrahydrofuran" title="Tetrahydrofuran">tetrahydrofuran</a>.<a href="#cite_note-cene-60">[59]</a> <div class="mw-heading mw-heading2"><h2 id="Applications">Applications</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=13" title="Edit section: Applications">edit</a>]</div> Although protactinium is situated in the periodic table between uranium and thorium, both of which have numerous applications, there are currently no uses for protactinium outside scientific research owing to its scarcity, high radioactivity, and high toxicity.<a href="#cite_note-ANL-38">[37]</a> Protactinium-231 arises naturally from the decay of natural uranium-235, and artificially in nuclear reactors by the reaction 232Th + n → 231Th + 2n and the subsequent <a href="/wiki/Beta_decay" title="Beta decay">beta decay</a> of 231Th. It was once thought to be able to support a nuclear chain reaction, which could in principle be used to build <a href="/wiki/Nuclear_weapon" title="Nuclear weapon">nuclear weapons</a>; the <a href="/wiki/Physicist" title="Physicist">physicist</a> <a href="/w/index.php?title=Walter_Seifritz&action=edit&redlink=1" class="new" title="Walter Seifritz (page does not exist)">Walter Seifritz</a> [<a href="https://de.wikipedia.org/wiki/Walter_Seifritz" class="extiw" title="de:Walter Seifritz">de</a>] once estimated the associated <a href="/wiki/Critical_mass" title="Critical mass">critical mass</a> as 750±180 kg.<a href="#cite_note-71">[70]</a> However, the possibility of criticality of 231Pa has since been ruled out.<a href="#cite_note-AVG231-36">[35]</a><a href="#cite_note-72">[71]</a> With the advent of highly sensitive <a href="/wiki/Mass_spectrometry" title="Mass spectrometry">mass spectrometers</a>, an application of 231Pa as a tracer in geology and <a href="/wiki/Paleoceanography" title="Paleoceanography">paleoceanography</a> has become possible. In this application, the ratio of protactinium-231 to thorium-230 is used for <a href="/wiki/Radiometric_dating" title="Radiometric dating">radiometric dating</a> of sediments which are up to 175,000 years old, and in modeling of the formation of minerals.<a href="#cite_note-brit-39">[38]</a> In particular, its evaluation in oceanic sediments helped to reconstruct the movements of <a href="/wiki/North_Atlantic" class="mw-redirect" title="North Atlantic">North Atlantic</a> water bodies during the last melting of <a href="/wiki/Ice_age" title="Ice age">Ice Age</a> <a href="/wiki/Glacier" title="Glacier">glaciers</a>.<a href="#cite_note-73">[72]</a> Some of the protactinium-related dating variations rely on analysis of the relative concentrations of several long-living members of the uranium decay chain – uranium, protactinium, and thorium, for example. These elements have 6, 5, and 4 valence electrons, thus favoring +6, +5, and +4 oxidation states respectively, and display different physical and chemical properties. Thorium and protactinium, but not uranium compounds, are poorly soluble in aqueous solutions and precipitate into sediments; the precipitation rate is faster for thorium than for protactinium. The concentration analysis for both protactinium-231 (half-life 32,760 years) and thorium-230 (half-life 75,380 years) improves measurement accuracy compared to when only one isotope is measured; this double-isotope method is also weakly sensitive to inhomogeneities in the spatial distribution of the isotopes and to variations in their precipitation rate.<a href="#cite_note-brit-39">[38]</a><a href="#cite_note-74">[73]</a> <div class="mw-heading mw-heading2"><h2 id="Precautions">Precautions</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=14" title="Edit section: Precautions">edit</a>]</div> Protactinium is both toxic and highly radioactive; thus, it is handled exclusively in a sealed <a href="/wiki/Glove_box" class="mw-redirect" title="Glove box">glove box</a>. Its major isotope 231Pa has a <a href="/wiki/Specific_activity" title="Specific activity">specific activity</a> of 0.048 <a href="/wiki/Curie_(unit)" title="Curie (unit)">curies</a> (1.8 <a href="/wiki/Becquerel" title="Becquerel">GBq</a>) per gram and primarily emits alpha-particles with an energy of 5 MeV, which can be stopped by a thin layer of any material. However, it slowly decays, with a half-life of 32,760 years, into 227Ac, which has a specific activity of 74 curies (2,700 GBq) per gram, emits both alpha and beta radiation, and has a much shorter half-life of 22 years. 227Ac, in turn, decays into lighter isotopes with even shorter half-lives and much greater specific activities (SA).<a href="#cite_note-ANL-38">[37]</a> <table class="wikitable" style="text-align:center"> <tbody><tr> <th>Isotope </th> <td>231Pa</td> <td>227Ac</td> <td>227Th</td> <td>223Ra</td> <td>219Rn</td> <td>215Po</td> <td>211Pb</td> <td>211Bi</td> <td>207Tl </td></tr> <tr> <th>SA (<a href="/wiki/Curie_(unit)" title="Curie (unit)">Ci</a>/g) </th> <td>0.048</td> <td>73</td> <td>3.1×104</td> <td>5.2×104</td> <td>1.3×1010</td> <td>3×1013</td> <td>2.5×107</td> <td>4.2×108</td> <td>1.9×108 </td></tr> <tr> <th>Decay </th> <td>α</td> <td>α, β</td> <td>α</td> <td>α</td> <td>α</td> <td>α</td> <td>β</td> <td>α, β</td> <td>β </td></tr> <tr> <th><a href="/wiki/Half-life" title="Half-life">Half-life</a> </th> <td>33 ka</td> <td>22 a</td> <td>19 days</td> <td>11 days</td> <td>4 s</td> <td>1.8 ms</td> <td>36 min</td> <td>2.1 min</td> <td>4.8 min </td></tr></tbody></table> As protactinium is present in small amounts in most natural products and materials, it is ingested with food or water and inhaled with air. Only about 0.05% of ingested protactinium is absorbed into the blood and the remainder is excreted. From the blood, about 40% of the protactinium deposits in the bones, about 15% goes to the liver, 2% to the kidneys, and the rest leaves the body. The biological half-life of protactinium is about 50 years in the bones, whereas its biological half-life in other organs has a fast and slow component. For example, 70% of the protactinium in the liver has a biological half-life of 10 days, and the remaining 30% for 60 days. The corresponding values for kidneys are 20% (10 days) and 80% (60 days). In each affected organ, protactinium promotes cancer via its radioactivity.<a href="#cite_note-ANL-38">[37]</a><a href="#cite_note-target-66">[65]</a> The maximum safe dose of Pa in the human body is 0.03 μCi (1.1 kBq), which corresponds to 0.5 micrograms of 231Pa.<a href="#cite_note-75">[74]</a> The maximum allowed concentrations of 231Pa in the air in Germany is 3×10−4 Bq/m3.<a href="#cite_note-target-66">[65]</a> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=15" title="Edit section: See also">edit</a>]</div> <ul><li><a href="/wiki/Ada_Hitchins" title="Ada Hitchins">Ada Hitchins</a>, who helped Soddy in discovering the element protactinium</li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=16" title="Edit section: Notes">edit</a>]</div> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-14"><a href="#cite_ref-14">^</a> The prefix "eka" is derived from the <a href="/wiki/Sanskrit" title="Sanskrit">Sanskrit</a> <a href="https://en.wiktionary.org/wiki/%E0%A4%8F%E0%A4%95#Sanskrit" class="extiw" title="wikt:एक"> एक</a>, meaning "one" or "first." In chemistry, it was formerly used to denote an element one period below the element name following it. </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=17" title="Edit section: References">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 35em;"> <ol class="references"> <li id="cite_note-CIAAW-1"><a href="#cite_ref-CIAAW_1-0">^</a> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ciaaw.org/protactinium.htm">"Standard Atomic Weights: Protactinium"</a>. <a href="/wiki/Commission_on_Isotopic_Abundances_and_Atomic_Weights" title="Commission on Isotopic Abundances and Atomic Weights">CIAAW</a>. 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Standard+Atomic+Weights%3A+Protactinium&rft.pub=CIAAW&rft.date=2017&rft_id=https%3A%2F%2Fwww.ciaaw.org%2Fprotactinium.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-CIAAW2021-2"><a href="#cite_ref-CIAAW2021_2-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFProhaskaIrrgeherBenefieldBöhlke2022" class="citation journal cs1">Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). <a rel="nofollow" class="external text" href="https://www.degruyter.com/document/doi/10.1515/pac-2019-0603/html">"Standard atomic weights of the elements 2021 (IUPAC Technical Report)"</a>. Pure and Applied Chemistry. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1515%2Fpac-2019-0603">10.1515/pac-2019-0603</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1365-3075">1365-3075</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Pure+and+Applied+Chemistry&rft.atitle=Standard+atomic+weights+of+the+elements+2021+%28IUPAC+Technical+Report%29&rft.date=2022-05-04&rft_id=info%3Adoi%2F10.1515%2Fpac-2019-0603&rft.issn=1365-3075&rft.aulast=Prohaska&rft.aufirst=Thomas&rft.au=Irrgeher%2C+Johanna&rft.au=Benefield%2C+Jacqueline&rft.au=B%C3%B6hlke%2C+John+K.&rft.au=Chesson%2C+Lesley+A.&rft.au=Coplen%2C+Tyler+B.&rft.au=Ding%2C+Tiping&rft.au=Dunn%2C+Philip+J.+H.&rft.au=Gr%C3%B6ning%2C+Manfred&rft.au=Holden%2C+Norman+E.&rft.au=Meijer%2C+Harro+A.+J.&rft_id=https%3A%2F%2Fwww.degruyter.com%2Fdocument%2Fdoi%2F10.1515%2Fpac-2019-0603%2Fhtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-Arblaster_2018-3">^ <a href="#cite_ref-Arblaster_2018_3-0">a</a> <a href="#cite_ref-Arblaster_2018_3-1">b</a> <a href="#cite_ref-Arblaster_2018_3-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFArblaster2018" class="citation book cs1">Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-62708-155-9" title="Special:BookSources/978-1-62708-155-9"><bdi>978-1-62708-155-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Selected+Values+of+the+Crystallographic+Properties+of+Elements&rft.place=Materials+Park%2C+Ohio&rft.pub=ASM+International&rft.date=2018&rft.isbn=978-1-62708-155-9&rft.aulast=Arblaster&rft.aufirst=John+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-GE28-4">^ <a href="#cite_ref-GE28_4-0">a</a> <a href="#cite_ref-GE28_4-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreenwoodEarnshaw1997" class="citation book cs1"><a href="/wiki/Norman_Greenwood" title="Norman Greenwood">Greenwood, Norman N.</a>; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). <a href="/wiki/Butterworth-Heinemann" title="Butterworth-Heinemann">Butterworth-Heinemann</a>. p. 28. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-08-037941-8" title="Special:BookSources/978-0-08-037941-8"><bdi>978-0-08-037941-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemistry+of+the+Elements&rft.pages=28&rft.edition=2nd&rft.pub=Butterworth-Heinemann&rft.date=1997&rft.isbn=978-0-08-037941-8&rft.aulast=Greenwood&rft.aufirst=Norman+N.&rft.au=Earnshaw%2C+Alan&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-str-5">^ <a href="#cite_ref-str_5-0">a</a> <a href="#cite_ref-str_5-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDonohue1959" class="citation journal cs1">Donohue, J. (1959). "On the crystal structure of protactinium metal". <a href="/wiki/Acta_Crystallographica" title="Acta Crystallographica">Acta Crystallographica</a>. 12 (9): 697. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS0365110X59002031">10.1107/S0365110X59002031</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica&rft.atitle=On+the+crystal+structure+of+protactinium+metal&rft.volume=12&rft.issue=9&rft.pages=697&rft.date=1959&rft_id=info%3Adoi%2F10.1107%2FS0365110X59002031&rft.aulast=Donohue&rft.aufirst=J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-magnet-6"><a href="#cite_ref-magnet_6-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLide,_D._R.2005" class="citation book cs1">Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110303222309/http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf">CRC Handbook of Chemistry and Physics</a> (PDF) (86th ed.). Boca Raton (FL): CRC Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-8493-0486-5" title="Special:BookSources/0-8493-0486-5"><bdi>0-8493-0486-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Magnetic+susceptibility+of+the+elements+and+inorganic+compounds&rft.btitle=CRC+Handbook+of+Chemistry+and+Physics&rft.place=Boca+Raton+%28FL%29&rft.edition=86th&rft.pub=CRC+Press&rft.date=2005&rft.isbn=0-8493-0486-5&rft_id=https%3A%2F%2Fweb.archive.org%2Fweb%2F20110303222309%2Fhttp%3A%2F%2Fwww-d0.fnal.gov%2Fhardware%2Fcal%2Flvps_info%2Fengineering%2Felementmagn.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-NUBASE2020-7"><a href="#cite_ref-NUBASE2020_7-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKondevWangHuangNaimi2021" class="citation journal cs1">Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). <a rel="nofollow" class="external text" href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf">"The NUBASE2020 evaluation of nuclear properties"</a> (PDF). Chinese Physics C. 45 (3): 030001. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F1674-1137%2Fabddae">10.1088/1674-1137/abddae</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chinese+Physics+C&rft.atitle=The+NUBASE2020+evaluation+of+nuclear+properties&rft.volume=45&rft.issue=3&rft.pages=030001&rft.date=2021&rft_id=info%3Adoi%2F10.1088%2F1674-1137%2Fabddae&rft.aulast=Kondev&rft.aufirst=F.+G.&rft.au=Wang%2C+M.&rft.au=Huang%2C+W.+J.&rft.au=Naimi%2C+S.&rft.au=Audi%2C+G.&rft_id=https%3A%2F%2Fwww-nds.iaea.org%2Famdc%2Fame2020%2FNUBASE2020.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-meitner-8">^ <a href="#cite_ref-meitner_8-0">a</a> <a href="#cite_ref-meitner_8-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMeitner1918" class="citation journal cs1">Meitner, Lise (1918). "Die Muttersubstanz des Actiniums, Ein Neues Radioaktives Element von Langer Lebensdauer". Zeitschrift für Elektrochemie und angewandte physikalische Chemie. 24 (11–12): 169–173. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fbbpc.19180241107">10.1002/bbpc.19180241107</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0372-8323">0372-8323</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Zeitschrift+f%C3%BCr+Elektrochemie+und+angewandte+physikalische+Chemie&rft.atitle=Die+Muttersubstanz+des+Actiniums%2C+Ein+Neues+Radioaktives+Element+von+Langer+Lebensdauer&rft.volume=24&rft.issue=%3Cspan+class%3D%22nowrap%22%3E11%E2%80%93%3C%2Fspan%3E12&rft.pages=%3Cspan+class%3D%22nowrap%22%3E169-%3C%2Fspan%3E173&rft.date=1918&rft_id=info%3Adoi%2F10.1002%2Fbbpc.19180241107&rft.issn=0372-8323&rft.aulast=Meitner&rft.aufirst=Lise&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-9"><a href="#cite_ref-9">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://hpschapters.org/northcarolina/NSDS/Protactinium.pdf">"Protactinium"</a> (PDF). Human Health Fact Sheet. ANL (Argonne National Laboratory). November 2001. Retrieved 4 September 2023. <q>The name comes from the Greek work protos (meaning first) and the element actinium, because protactinium is the precursor of actinium.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Human+Health+Fact+Sheet&rft.atitle=Protactinium&rft.date=2001-11&rft_id=http%3A%2F%2Fhpschapters.org%2Fnorthcarolina%2FNSDS%2FProtactinium.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-10"><a href="#cite_ref-10">^</a> <a rel="nofollow" class="external text" href="http://www.universitystory.gla.ac.uk/biography/?id=WH3023&type=P">John Arnold Cranston</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200311015550/http://www.universitystory.gla.ac.uk/biography/?id=WH3023&type=P">Archived</a> 11 March 2020 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>. <a href="/wiki/University_of_Glasgow" title="University of Glasgow">University of Glasgow</a> </li> <li id="cite_note-11"><a href="#cite_ref-11">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNegre2010" class="citation journal cs1">Negre, César; et al. (2010). <a rel="nofollow" class="external text" href="https://www.pure.ed.ac.uk/ws/files/11751410/ReversedATlantic_Deep.pdf">"Reversed flow of Atlantic deep water during the Last Glacial Maximum"</a> (PDF). Nature. 468 (7320): 84–8. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2010Natur.468...84N">2010Natur.468...84N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature09508">10.1038/nature09508</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/21048764">21048764</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Reversed+flow+of+Atlantic+deep+water+during+the+Last+Glacial+Maximum&rft.volume=468&rft.issue=7320&rft.pages=%3Cspan+class%3D%22nowrap%22%3E84-%3C%2Fspan%3E8&rft.date=2010&rft_id=info%3Apmid%2F21048764&rft_id=info%3Adoi%2F10.1038%2Fnature09508&rft_id=info%3Abibcode%2F2010Natur.468...84N&rft.aulast=Negre&rft.aufirst=C%C3%A9sar&rft_id=https%3A%2F%2Fwww.pure.ed.ac.uk%2Fws%2Ffiles%2F11751410%2FReversedATlantic_Deep.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-Emsley-12">^ <a href="#cite_ref-Emsley_12-0">a</a> <a href="#cite_ref-Emsley_12-1">b</a> <a href="#cite_ref-Emsley_12-2">c</a> <a href="#cite_ref-Emsley_12-3">d</a> <a href="#cite_ref-Emsley_12-4">e</a> <a href="#cite_ref-Emsley_12-5">f</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEmsley2003" class="citation book cs1">Emsley, John (2003) [2001]. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=j-Xu07p3cKwC&pg=PA348">"Protactinium"</a>. <a rel="nofollow" class="external text" href="https://archive.org/details/naturesbuildingb0000emsl/page/347">Nature's Building Blocks: An A-Z Guide to the Elements</a>. Oxford, England, UK: Oxford University Press. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/naturesbuildingb0000emsl/page/347">347–349</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-850340-8" title="Special:BookSources/978-0-19-850340-8"><bdi>978-0-19-850340-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Protactinium&rft.btitle=Nature%27s+Building+Blocks%3A+An+A-Z+Guide+to+the+Elements&rft.place=Oxford%2C+England%2C+UK&rft.pages=347-349&rft.pub=Oxford+University+Press&rft.date=2003&rft.isbn=978-0-19-850340-8&rft.aulast=Emsley&rft.aufirst=John&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dj-Xu07p3cKwC%26pg%3DPA348&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-13"><a href="#cite_ref-13">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLaing,_Michael2005" class="citation journal cs1">Laing, Michael (2005). "A Revised Periodic Table: With the Lanthanides Repositioned". <a href="/wiki/Foundations_of_Chemistry" title="Foundations of Chemistry">Foundations of Chemistry</a>. 7 (3): 203. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs10698-004-5959-9">10.1007/s10698-004-5959-9</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:97792365">97792365</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Foundations+of+Chemistry&rft.atitle=A+Revised+Periodic+Table%3A+With+the+Lanthanides+Repositioned&rft.volume=7&rft.issue=3&rft.pages=203&rft.date=2005&rft_id=info%3Adoi%2F10.1007%2Fs10698-004-5959-9&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A97792365%23id-name%3DS2CID&rft.au=Laing%2C+Michael&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-Fessl-15"><a href="#cite_ref-Fessl_15-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFessl2019" class="citation web cs1">Fessl, Sophie (2 January 2019). <a rel="nofollow" class="external text" href="https://daily.jstor.org/how-far-does-the-periodic-table-go/">"How Far Does the Periodic Table Go?"</a>. JSTOR. Retrieved 9 January 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=How+Far+Does+the+Periodic+Table+Go%3F&rft.pub=JSTOR&rft.date=2019-01-02&rft.aulast=Fessl&rft.aufirst=Sophie&rft_id=https%3A%2F%2Fdaily.jstor.org%2Fhow-far-does-the-periodic-table-go%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-google-16"><a href="#cite_ref-google_16-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNational_Research_Council_(U.S.)._Conference_on_Glossary_of_Terms_in_Nuclear_Science_and_Technology1957" class="citation book cs1">National Research Council (U.S.). Conference on Glossary of Terms in Nuclear Science and Technology (1957). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=-zgrAAAAYAAJ&pg=PA180">A Glossary of Terms in Nuclear Science and Technology</a>. American Society of Mechanical Engineers. p. 180. Retrieved 25 July 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Glossary+of+Terms+in+Nuclear+Science+and+Technology&rft.pages=180&rft.pub=American+Society+of+Mechanical+Engineers&rft.date=1957&rft.au=National+Research+Council+%28U.S.%29.+Conference+on+Glossary+of+Terms+in+Nuclear+Science+and+Technology&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D-zgrAAAAYAAJ%26pg%3DPA180&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-17"><a href="#cite_ref-17">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrookes1899" class="citation journal cs1">Crookes, W. (1899). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=hmZDAAAAYAAJ&pg=PA409-IA6">"Radio-Activity of Uranium"</a>. <a href="/wiki/Proceedings_of_the_Royal_Society_of_London" class="mw-redirect" title="Proceedings of the Royal Society of London">Proceedings of the Royal Society of London</a>. 66 (424–433): 409–423. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frspl.1899.0120">10.1098/rspl.1899.0120</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:93563820">93563820</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Royal+Society+of+London&rft.atitle=Radio-Activity+of+Uranium&rft.volume=66&rft.issue=%3Cspan+class%3D%22nowrap%22%3E424%E2%80%93%3C%2Fspan%3E433&rft.pages=%3Cspan+class%3D%22nowrap%22%3E409-%3C%2Fspan%3E423&rft.date=1899&rft_id=info%3Adoi%2F10.1098%2Frspl.1899.0120&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A93563820%23id-name%3DS2CID&rft.aulast=Crookes&rft.aufirst=W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DhmZDAAAAYAAJ%26pg%3DPA409-IA6&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-18"><a href="#cite_ref-18">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJohansson1954" class="citation journal cs1">Johansson, Sven (1954). "Decay of UX1, UX2, and UZ". <a href="/wiki/Physical_Review" title="Physical Review">Physical Review</a>. 96 (4): 1075–1080. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1954PhRv...96.1075J">1954PhRv...96.1075J</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.96.1075">10.1103/PhysRev.96.1075</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review&rft.atitle=Decay+of+UX1%2C+UX2%2C+and+UZ&rft.volume=96&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1075-%3C%2Fspan%3E1080&rft.date=1954&rft_id=info%3Adoi%2F10.1103%2FPhysRev.96.1075&rft_id=info%3Abibcode%2F1954PhRv...96.1075J&rft.aulast=Johansson&rft.aufirst=Sven&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1250-19"><a href="#cite_ref-g1250_19-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1250 </li> <li id="cite_note-g1254-20"><a href="#cite_ref-g1254_20-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1254 </li> <li id="cite_note-21"><a href="#cite_ref-21">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFajans,_K.Gohring,_O.1913" class="citation journal cs1">Fajans, K. & Gohring, O. (1913). <a rel="nofollow" class="external text" href="http://www.digizeitschriften.de/no_cache/home/jkdigitools/loader/?tx_jkDigiTools_pi1%5BIDDOC%5D=201162&tx_jkDigiTools_pi1%5Bpp%5D=425">"Über die komplexe Natur des Ur X"</a>. <a href="/wiki/Naturwissenschaften" class="mw-redirect" title="Naturwissenschaften">Naturwissenschaften</a>. 1 (14): 339. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1913NW......1..339F">1913NW......1..339F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF01495360">10.1007/BF01495360</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:40667401">40667401</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Naturwissenschaften&rft.atitle=%C3%9Cber+die+komplexe+Natur+des+Ur+X&rft.volume=1&rft.issue=14&rft.pages=339&rft.date=1913&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A40667401%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF01495360&rft_id=info%3Abibcode%2F1913NW......1..339F&rft.au=Fajans%2C+K.&rft.au=Gohring%2C+O.&rft_id=http%3A%2F%2Fwww.digizeitschriften.de%2Fno_cache%2Fhome%2Fjkdigitools%2Floader%2F%3Ftx_jkDigiTools_pi1%255BIDDOC%255D%3D201162%26tx_jkDigiTools_pi1%255Bpp%255D%3D425&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-22"><a href="#cite_ref-22">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFajans,_K.Gohring,_O.1913" class="citation journal cs1">Fajans, K. & Gohring, O. (1913). "Über das Uran X2-das neue Element der Uranreihe". <a href="/wiki/Physikalische_Zeitschrift" title="Physikalische Zeitschrift">Physikalische Zeitschrift</a>. 14: 877–84.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physikalische+Zeitschrift&rft.atitle=%C3%9Cber+das+Uran+X%3Csub%3E2%3C%2Fsub%3E-das+neue+Element+der+Uranreihe&rft.volume=14&rft.pages=%3Cspan+class%3D%22nowrap%22%3E877-%3C%2Fspan%3E84&rft.date=1913&rft.au=Fajans%2C+K.&rft.au=Gohring%2C+O.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-Scerri-23">^ <a href="#cite_ref-Scerri_23-0">a</a> <a href="#cite_ref-Scerri_23-1">b</a> <a href="/wiki/Eric_Scerri" title="Eric Scerri">Eric Scerri</a>, A tale of seven elements, (Oxford University Press 2013) <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-539131-2" title="Special:BookSources/978-0-19-539131-2">978-0-19-539131-2</a>, p.67–74 </li> <li id="cite_note-PaIsoDisc-24"><a href="#cite_ref-PaIsoDisc_24-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFajansMorris1973" class="citation journal cs1">Fajans, K.; Morris, D. F. C. (1973). <a rel="nofollow" class="external text" href="https://deepblue.lib.umich.edu/bitstream/handle/2027.42/62921/244137a0.pdf">"Discovery and Naming of the Isotopes of Element 91"</a> (PDF). Nature. 244 (5412): 137–138. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1973Natur.244..137F">1973Natur.244..137F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F244137a0">10.1038/244137a0</a>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/2027.42%2F62921">2027.42/62921</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Discovery+and+Naming+of+the+Isotopes+of+Element+91&rft.volume=244&rft.issue=5412&rft.pages=%3Cspan+class%3D%22nowrap%22%3E137-%3C%2Fspan%3E138&rft.date=1973&rft_id=info%3Ahdl%2F2027.42%2F62921&rft_id=info%3Adoi%2F10.1038%2F244137a0&rft_id=info%3Abibcode%2F1973Natur.244..137F&rft.aulast=Fajans&rft.aufirst=K.&rft.au=Morris%2C+D.+F.+C.&rft_id=https%3A%2F%2Fdeepblue.lib.umich.edu%2Fbitstream%2Fhandle%2F2027.42%2F62921%2F244137a0.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-25"><a href="#cite_ref-25">^</a> <a rel="nofollow" class="external text" href="https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1918.0025">Soddy, F., Cranston, J.F. (1918) The parent of actinium</a>. Proceedings of the Royal Society A – Mathematical, Physical and Engineering Sciences 94: 384-403. </li> <li id="cite_note-26"><a href="#cite_ref-26">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.rsc.org/periodic-table/element/91/protactinium">"Protactinium - Element information : Chemistry in its element: protactinium"</a>. www.rsc.org. <a href="/wiki/Royal_Society_of_Chemistry" title="Royal Society of Chemistry">Royal Society of Chemistry</a>. Retrieved 20 October 2023. <q>At this point Fajans withdrew the name brevium since the custom was to name an element according to longest-lived isotope. Meitner than chose the name protactinium.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.rsc.org&rft.atitle=Protactinium+-+Element+information+%3A+Chemistry+in+its+element%3A+protactinium&rft_id=https%3A%2F%2Fwww.rsc.org%2Fperiodic-table%2Felement%2F91%2Fprotactinium&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-CRC-27">^ <a href="#cite_ref-CRC_27-0">a</a> <a href="#cite_ref-CRC_27-1">b</a> <a href="#cite_ref-CRC_27-2">c</a> <a href="#cite_ref-CRC_27-3">d</a> <a href="#cite_ref-CRC_27-4">e</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHammond,_C._R.2004" class="citation book cs1">Hammond, C. R. (29 June 2004). <a rel="nofollow" class="external text" href="https://archive.org/details/crchandbookofche81lide">The Elements, in Handbook of Chemistry and Physics</a> (81st ed.). CRC press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8493-0485-9" title="Special:BookSources/978-0-8493-0485-9"><bdi>978-0-8493-0485-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Elements%2C+in+Handbook+of+Chemistry+and+Physics&rft.edition=81st&rft.pub=CRC+press&rft.date=2004-06-29&rft.isbn=978-0-8493-0485-9&rft.au=Hammond%2C+C.+R.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fcrchandbookofche81lide&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1251-28"><a href="#cite_ref-g1251_28-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1251 </li> <li id="cite_note-29"><a href="#cite_ref-29">^</a> Shea, William R. (1983) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=W7xyvXc-hgEC&pg=PA213">Otto Hahn and the rise of nuclear physics</a>, Springer, p. 213, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/90-277-1584-X" title="Special:BookSources/90-277-1584-X">90-277-1584-X</a>. </li> <li id="cite_note-30"><a href="#cite_ref-30">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFvon_Grosse,_Aristid1928" class="citation journal cs1">von Grosse, Aristid (1928). "Das Element 91; seine Eigenschaften und seine Gewinnung". <a href="/wiki/Berichte_der_deutschen_chemischen_Gesellschaft" class="mw-redirect" title="Berichte der deutschen chemischen Gesellschaft">Berichte der deutschen chemischen Gesellschaft</a>. 61 (1): 233–245. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fcber.19280610137">10.1002/cber.19280610137</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Berichte+der+deutschen+chemischen+Gesellschaft&rft.atitle=Das+Element+91%3B+seine+Eigenschaften+und+seine+Gewinnung&rft.volume=61&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E233-%3C%2Fspan%3E245&rft.date=1928&rft_id=info%3Adoi%2F10.1002%2Fcber.19280610137&rft.au=von+Grosse%2C+Aristid&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-31"><a href="#cite_ref-31">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGraueKäding1934" class="citation journal cs1">Graue, G.; Käding, H. (1934). "Die technische Gewinnung des Protactiniums". <a href="/wiki/Angewandte_Chemie" title="Angewandte Chemie">Angewandte Chemie</a>. 47 (37): 650–653. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1934AngCh..47..650G">1934AngCh..47..650G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fange.19340473706">10.1002/ange.19340473706</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Angewandte+Chemie&rft.atitle=Die+technische+Gewinnung+des+Protactiniums&rft.volume=47&rft.issue=37&rft.pages=%3Cspan+class%3D%22nowrap%22%3E650-%3C%2Fspan%3E653&rft.date=1934&rft_id=info%3Adoi%2F10.1002%2Fange.19340473706&rft_id=info%3Abibcode%2F1934AngCh..47..650G&rft.aulast=Graue&rft.aufirst=G.&rft.au=K%C3%A4ding%2C+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-32"><a href="#cite_ref-32">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrosse1934" class="citation journal cs1">Grosse, A. V. (1934). "Metallic Element 91". <a href="/wiki/Journal_of_the_American_Chemical_Society" title="Journal of the American Chemical Society">Journal of the American Chemical Society</a>. 56 (10): 2200–2201. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1934JAChS..56R2200G">1934JAChS..56R2200G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fja01325a508">10.1021/ja01325a508</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=Metallic+Element+91&rft.volume=56&rft.issue=10&rft.pages=%3Cspan+class%3D%22nowrap%22%3E2200-%3C%2Fspan%3E2201&rft.date=1934&rft_id=info%3Adoi%2F10.1021%2Fja01325a508&rft_id=info%3Abibcode%2F1934JAChS..56R2200G&rft.aulast=Grosse&rft.aufirst=A.+V.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-Myasoedov-33">^ <a href="#cite_ref-Myasoedov_33-0">a</a> <a href="#cite_ref-Myasoedov_33-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMyasoedovKirbyTananaev2006" class="citation book cs1">Myasoedov, B. F.; Kirby, H. W.; Tananaev, I. G. (2006). "Chapter 4: Protactinium". In Morss, L. R.; Edelstein, N. M.; Fuger, J. (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2011tcot.book.....M">2011tcot.book.....M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2F978-94-007-0211-0">10.1007/978-94-007-0211-0</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4020-3555-5" title="Special:BookSources/978-1-4020-3555-5"><bdi>978-1-4020-3555-5</bdi></a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:93796247">93796247</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Chapter+4%3A+Protactinium&rft.btitle=The+Chemistry+of+the+Actinide+and+Transactinide+Elements&rft.place=Dordrecht%2C+The+Netherlands&rft.edition=3rd&rft.pub=Springer&rft.date=2006&rft_id=info%3Adoi%2F10.1007%2F978-94-007-0211-0&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A93796247%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2011tcot.book.....M&rft.isbn=978-1-4020-3555-5&rft.aulast=Myasoedov&rft.aufirst=B.+F.&rft.au=Kirby%2C+H.+W.&rft.au=Tananaev%2C+I.+G.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-34"><a href="#cite_ref-34">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110928025549/http://periodic.lanl.gov/91.shtml">"Periodic Table of Elements: Protactinium"</a>. <a href="/wiki/Los_Alamos_National_Laboratory" title="Los Alamos National Laboratory">Los Alamos National Laboratory</a>. Archived from <a rel="nofollow" class="external text" href="https://periodic.lanl.gov/91.shtml">the original</a> on 28 September 2011. Retrieved 21 March 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Periodic+Table+of+Elements%3A+Protactinium&rft.pub=Los+Alamos+National+Laboratory&rft_id=https%3A%2F%2Fperiodic.lanl.gov%2F91.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-nubase-35">^ <a href="#cite_ref-nubase_35-0">a</a> <a href="#cite_ref-nubase_35-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAudiBersillonBlachotWapstra2003" class="citation cs2">Audi, Georges; Bersillon, Olivier; Blachot, Jean; <a href="/wiki/Aaldert_Wapstra" title="Aaldert Wapstra">Wapstra, Aaldert Hendrik</a> (2003), <a rel="nofollow" class="external text" href="https://hal.archives-ouvertes.fr/in2p3-00020241/document">"The NUBASE evaluation of nuclear and decay properties"</a>, Nuclear Physics A, 729: 3–128, <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2003NuPhA.729....3A">2003NuPhA.729....3A</a>, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.nuclphysa.2003.11.001">10.1016/j.nuclphysa.2003.11.001</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nuclear+Physics+A&rft.atitle=The+N%3Csmall%3EUBASE%3C%2Fsmall%3E+evaluation+of+nuclear+and+decay+properties&rft.volume=729&rft.pages=%3Cspan+class%3D%22nowrap%22%3E3-%3C%2Fspan%3E128&rft.date=2003&rft_id=info%3Adoi%2F10.1016%2Fj.nuclphysa.2003.11.001&rft_id=info%3Abibcode%2F2003NuPhA.729....3A&rft.aulast=Audi&rft.aufirst=Georges&rft.au=Bersillon%2C+Olivier&rft.au=Blachot%2C+Jean&rft.au=Wapstra%2C+Aaldert+Hendrik&rft_id=https%3A%2F%2Fhal.archives-ouvertes.fr%2Fin2p3-00020241%2Fdocument&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-AVG231-36">^ <a href="#cite_ref-AVG231_36-0">a</a> <a href="#cite_ref-AVG231_36-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrosseBoothDunning1939" class="citation journal cs1">Grosse, A. v.; Booth, E. T.; Dunning, J. R. (15 August 1939). <a rel="nofollow" class="external text" href="https://journals.aps.org/pr/pdf/10.1103/PhysRev.56.382">"The Fission of Protactinium (Element 91)"</a>. Physical Review. 56 (4): 382. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1939PhRv...56..382G">1939PhRv...56..382G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.56.382">10.1103/PhysRev.56.382</a>. Retrieved 17 February 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review&rft.atitle=The+Fission+of+Protactinium+%28Element+91%29&rft.volume=56&rft.issue=4&rft.pages=382&rft.date=1939-08-15&rft_id=info%3Adoi%2F10.1103%2FPhysRev.56.382&rft_id=info%3Abibcode%2F1939PhRv...56..382G&rft.aulast=Grosse&rft.aufirst=A.+v.&rft.au=Booth%2C+E.+T.&rft.au=Dunning%2C+J.+R.&rft_id=https%3A%2F%2Fjournals.aps.org%2Fpr%2Fpdf%2F10.1103%2FPhysRev.56.382&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-37"><a href="#cite_ref-37">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTovessonHambschOberstedtFogelberg2002" class="citation journal cs1">Tovesson, F.; Hambsch, F.-J; Oberstedt, A.; Fogelberg, B.; Ramström, E.; Oberstedt, S. (August 2002). <a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F00223131.2002.10875076">"The Pa-233 Fission Cross Section"</a>. Journal of Nuclear Science and Technology. 39 (sup2): 210–213. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002JNST...39Q.210T">2002JNST...39Q.210T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F00223131.2002.10875076">10.1080/00223131.2002.10875076</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:91866777">91866777</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Nuclear+Science+and+Technology&rft.atitle=The+Pa-233+Fission+Cross+Section&rft.volume=39&rft.issue=sup2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E210-%3C%2Fspan%3E213&rft.date=2002-08&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A91866777%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1080%2F00223131.2002.10875076&rft_id=info%3Abibcode%2F2002JNST...39Q.210T&rft.aulast=Tovesson&rft.aufirst=F.&rft.au=Hambsch%2C+F.-J&rft.au=Oberstedt%2C+A.&rft.au=Fogelberg%2C+B.&rft.au=Ramstr%C3%B6m%2C+E.&rft.au=Oberstedt%2C+S.&rft_id=https%3A%2F%2Fdoi.org%2F10.1080%252F00223131.2002.10875076&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-ANL-38">^ <a href="#cite_ref-ANL_38-0">a</a> <a href="#cite_ref-ANL_38-1">b</a> <a href="#cite_ref-ANL_38-2">c</a> <a href="#cite_ref-ANL_38-3">d</a> <a href="#cite_ref-ANL_38-4">e</a> <a rel="nofollow" class="external text" href="http://www.ead.anl.gov/pub/doc/protactinium.pdf">Protactinium</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080307023843/http://www.ead.anl.gov/pub/doc/protactinium.pdf">Archived</a> 7 March 2008 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, Argonne National Laboratory, Human Health Fact Sheet, August 2005 </li> <li id="cite_note-brit-39">^ <a href="#cite_ref-brit_39-0">a</a> <a href="#cite_ref-brit_39-1">b</a> <a href="#cite_ref-brit_39-2">c</a> Articles "Protactinium" and "Protactinium-231 – thorium-230 dating" in Encyclopædia Britannica, 15th edition, 1995, p. 737 </li> <li id="cite_note-40"><a href="#cite_ref-40">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrosseAgruss1934" class="citation journal cs1">Grosse, A. V.; Agruss, M. S. (1934). "The Isolation of 0.1 Gram of the Oxide of Element 91 (Protactinium)". <a href="/wiki/Journal_of_the_American_Chemical_Society" title="Journal of the American Chemical Society">Journal of the American Chemical Society</a>. 56 (10): 2200. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1934JAChS..56Q2200G">1934JAChS..56Q2200G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fja01325a507">10.1021/ja01325a507</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=The+Isolation+of+0.1+Gram+of+the+Oxide+of+Element+91+%28Protactinium%29&rft.volume=56&rft.issue=10&rft.pages=2200&rft.date=1934&rft_id=info%3Adoi%2F10.1021%2Fja01325a507&rft_id=info%3Abibcode%2F1934JAChS..56Q2200G&rft.aulast=Grosse&rft.aufirst=A.+V.&rft.au=Agruss%2C+M.+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-41"><a href="#cite_ref-41">^</a> Cornelis, Rita (2005) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=1PmjurlE6KkC&pg=PA520">Handbook of elemental speciation II: species in the environment, food, medicine & occupational health, Vol. 2</a>, John Wiley and Sons, pp. 520–521, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-470-85598-3" title="Special:BookSources/0-470-85598-3">0-470-85598-3</a>. </li> <li id="cite_note-b1-42">^ <a href="#cite_ref-b1_42-0">a</a> <a href="#cite_ref-b1_42-1">b</a> Groult, Henri (2005) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dR2DA50PUV4C&pg=PA562">Fluorinated materials for energy conversion</a>, Elsevier, pp. 562–565, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-08-044472-5" title="Special:BookSources/0-08-044472-5">0-08-044472-5</a>. </li> <li id="cite_note-43"><a href="#cite_ref-43">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHébert,_Alain2009" class="citation book cs1">Hébert, Alain (July 2009). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=sibA5ECQ8LoC&pg=PA265">Applied Reactor Physics</a>. Presses inter Polytechnique. p. 265. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-2-553-01436-9" title="Special:BookSources/978-2-553-01436-9"><bdi>978-2-553-01436-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Applied+Reactor+Physics&rft.pages=265&rft.pub=Presses+inter+Polytechnique&rft.date=2009-07&rft.isbn=978-2-553-01436-9&rft.au=H%C3%A9bert%2C+Alain&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DsibA5ECQ8LoC%26pg%3DPA265&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-exp-44">^ <a href="#cite_ref-exp_44-0">a</a> <a href="#cite_ref-exp_44-1">b</a> <a href="#cite_ref-exp_44-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMarples1965" class="citation journal cs1">Marples, J. A. C. (1965). "On the thermal expansion of protactinium metal". <a href="/wiki/Acta_Crystallographica" title="Acta Crystallographica">Acta Crystallographica</a>. 18 (4): 815–817. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1965AcCry..18..815M">1965AcCry..18..815M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS0365110X65001871">10.1107/S0365110X65001871</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica&rft.atitle=On+the+thermal+expansion+of+protactinium+metal&rft.volume=18&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E815-%3C%2Fspan%3E817&rft.date=1965&rft_id=info%3Adoi%2F10.1107%2FS0365110X65001871&rft_id=info%3Abibcode%2F1965AcCry..18..815M&rft.aulast=Marples&rft.aufirst=J.+A.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-super-45">^ <a href="#cite_ref-super_45-0">a</a> <a href="#cite_ref-super_45-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFowler,_R._D.MatthiasAspreyHill1965" class="citation journal cs1">Fowler, R. D.; Matthias, B.; Asprey, L.; Hill, H.; et al. (1965). "Superconductivity of Protactinium". <a href="/wiki/Physical_Review_Letters" title="Physical Review Letters">Physical Review Letters</a>. 15 (22): 860. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1965PhRvL..15..860F">1965PhRvL..15..860F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevLett.15.860">10.1103/PhysRevLett.15.860</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+Letters&rft.atitle=Superconductivity+of+Protactinium&rft.volume=15&rft.issue=22&rft.pages=860&rft.date=1965&rft_id=info%3Adoi%2F10.1103%2FPhysRevLett.15.860&rft_id=info%3Abibcode%2F1965PhRvL..15..860F&rft.au=Fowler%2C+R.+D.&rft.au=Matthias%2C+B.&rft.au=Asprey%2C+L.&rft.au=Hill%2C+H.&rft.au=Lindsay%2C+J.&rft.au=Olsen%2C+C.&rft.au=White%2C+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-pao2-46">^ <a href="#cite_ref-pao2_46-0">a</a> <a href="#cite_ref-pao2_46-1">b</a> <a href="#cite_ref-pao2_46-2">c</a> <a href="#cite_ref-pao2_46-3">d</a> <a href="#cite_ref-pao2_46-4">e</a> <a href="#cite_ref-pao2_46-5">f</a> <a href="#cite_ref-pao2_46-6">g</a> <a href="#cite_ref-pao2_46-7">h</a> <a href="#cite_ref-pao2_46-8">i</a> <a href="#cite_ref-pao2_46-9">j</a> <a href="#cite_ref-pao2_46-10">k</a> <a href="#cite_ref-pao2_46-11">l</a> <a href="#cite_ref-pao2_46-12">m</a> <a href="#cite_ref-pao2_46-13">n</a> <a href="#cite_ref-pao2_46-14">o</a> <a href="#cite_ref-pao2_46-15">p</a> <a href="#cite_ref-pao2_46-16">q</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSellersFriedElsonZachariasen1954" class="citation journal cs1">Sellers, Philip A.; Fried, Sherman; Elson, Robert E.; Zachariasen, W. H. (1954). <a rel="nofollow" class="external text" href="https://digital.library.unt.edu/ark:/67531/metadc172625/">"The Preparation of Some Protactinium Compounds and the Metal"</a>. <a href="/wiki/Journal_of_the_American_Chemical_Society" title="Journal of the American Chemical Society">Journal of the American Chemical Society</a>. 76 (23): 5935. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1954JAChS..76.5935S">1954JAChS..76.5935S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fja01652a011">10.1021/ja01652a011</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=The+Preparation+of+Some+Protactinium+Compounds+and+the+Metal&rft.volume=76&rft.issue=23&rft.pages=5935&rft.date=1954&rft_id=info%3Adoi%2F10.1021%2Fja01652a011&rft_id=info%3Abibcode%2F1954JAChS..76.5935S&rft.aulast=Sellers&rft.aufirst=Philip+A.&rft.au=Fried%2C+Sherman&rft.au=Elson%2C+Robert+E.&rft.au=Zachariasen%2C+W.+H.&rft_id=https%3A%2F%2Fdigital.library.unt.edu%2Fark%3A%2F67531%2Fmetadc172625%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-47"><a href="#cite_ref-47">^</a> Seitz, Frederick and Turnbull, David (1964) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=F9V3a-0V3r8C&pg=PA289">Solid state physics: advances in research and applications</a>, Academic Press, pp. 289–291, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-12-607716-9" title="Special:BookSources/0-12-607716-9">0-12-607716-9</a>. </li> <li id="cite_note-48"><a href="#cite_ref-48">^</a> Young, David A. (1991) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=F2HVYh6wLBcC&pg=PA222">Phase diagrams of the elements</a>, University of California Press, p. 222, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-520-07483-1" title="Special:BookSources/0-520-07483-1">0-520-07483-1</a>. </li> <li id="cite_note-49"><a href="#cite_ref-49">^</a> Buschow, K. H. J. (2005) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=N9mvytGEBtwC&pg=PA129">Concise encyclopedia of magnetic and superconducting materials</a>, Elsevier, pp. 129–130, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-08-044586-1" title="Special:BookSources/0-08-044586-1">0-08-044586-1</a>. </li> <li id="cite_note-50"><a href="#cite_ref-50">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHendricks1971" class="citation journal cs1">Hendricks, M. E. (1971). "Magnetic Properties of Protactinium Tetrachloride". <a href="/wiki/Journal_of_Chemical_Physics" class="mw-redirect" title="Journal of Chemical Physics">Journal of Chemical Physics</a>. 55 (6): 2993–2997. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1971JChPh..55.2993H">1971JChPh..55.2993H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1063%2F1.1676528">10.1063/1.1676528</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Physics&rft.atitle=Magnetic+Properties+of+Protactinium+Tetrachloride&rft.volume=55&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E2993-%3C%2Fspan%3E2997&rft.date=1971&rft_id=info%3Adoi%2F10.1063%2F1.1676528&rft_id=info%3Abibcode%2F1971JChPh..55.2993H&rft.aulast=Hendricks&rft.aufirst=M.+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1265-51"><a href="#cite_ref-g1265_51-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1265 </li> <li id="cite_note-g1275-52">^ <a href="#cite_ref-g1275_52-0">a</a> <a href="#cite_ref-g1275_52-1">b</a> <a href="#Greenwood">Greenwood</a>, p. 1275 </li> <li id="cite_note-trif-53">^ <a href="#cite_ref-trif_53-0">a</a> <a href="#cite_ref-trif_53-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAspreyKruseRosenzweigPenneman1966" class="citation journal cs1">Asprey, L. B.; Kruse, F. H.; Rosenzweig, A.; Penneman, R. A. (1966). "Synthesis and X-Ray Properties of Alkali Fluoride-Protactinium Pentafluoride Complexes". <a href="/wiki/Inorganic_Chemistry_(journal)" title="Inorganic Chemistry (journal)">Inorganic Chemistry</a>. 5 (4): 659. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fic50038a034">10.1021/ic50038a034</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Inorganic+Chemistry&rft.atitle=Synthesis+and+X-Ray+Properties+of+Alkali+Fluoride-Protactinium+Pentafluoride+Complexes&rft.volume=5&rft.issue=4&rft.pages=659&rft.date=1966&rft_id=info%3Adoi%2F10.1021%2Fic50038a034&rft.aulast=Asprey&rft.aufirst=L.+B.&rft.au=Kruse%2C+F.+H.&rft.au=Rosenzweig%2C+A.&rft.au=Penneman%2C+R.+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-54"><a href="#cite_ref-54">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrown_D.Hall_T.L.Moseley_P.T1973" class="citation journal cs1">Brown D.; Hall T.L.; Moseley P.T (1973). "Structural parameters and unit cell dimensions for the tetragonal actinide tetrachlorides(Th, Pa, U, and Np) and tetrabromides (Th and Pa)". <a href="/wiki/Journal_of_the_Chemical_Society,_Dalton_Transactions" class="mw-redirect" title="Journal of the Chemical Society, Dalton Transactions">Journal of the Chemical Society, Dalton Transactions</a> (6): 686–691. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1039%2FDT9730000686">10.1039/DT9730000686</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+Chemical+Society%2C+Dalton+Transactions&rft.atitle=Structural+parameters+and+unit+cell+dimensions+for+the+tetragonal+actinide+tetrachlorides%28Th%2C+Pa%2C+U%2C+and+Np%29+and+tetrabromides+%28Th+and+Pa%29&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E686-%3C%2Fspan%3E691&rft.date=1973&rft_id=info%3Adoi%2F10.1039%2FDT9730000686&rft.au=Brown+D.&rft.au=Hall+T.L.&rft.au=Moseley+P.T&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-pabr4-55"><a href="#cite_ref-pabr4_55-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTahriChermetteEl_KhatibKrupa1990" class="citation journal cs1">Tahri, Y.; Chermette, H.; El Khatib, N.; Krupa, J.; et al. (1990). "Electronic structures of thorium and protactinium halide clusters of [ThX8]4− type". <a href="/wiki/Journal_of_the_Less_Common_Metals" class="mw-redirect" title="Journal of the Less Common Metals">Journal of the Less Common Metals</a>. 158: 105–116. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-5088%2890%2990436-N">10.1016/0022-5088(90)90436-N</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+Less+Common+Metals&rft.atitle=Electronic+structures+of+thorium+and+protactinium+halide+clusters+of+%5BThX8%5D4%E2%88%92+type&rft.volume=158&rft.pages=%3Cspan+class%3D%22nowrap%22%3E105-%3C%2Fspan%3E116&rft.date=1990&rft_id=info%3Adoi%2F10.1016%2F0022-5088%2890%2990436-N&rft.aulast=Tahri&rft.aufirst=Y.&rft.au=Chermette%2C+H.&rft.au=El+Khatib%2C+N.&rft.au=Krupa%2C+J.&rft.au=Simoni%2C+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-pabr5b-56">^ <a href="#cite_ref-pabr5b_56-0">a</a> <a href="#cite_ref-pabr5b_56-1">b</a> <a href="#cite_ref-pabr5b_56-2">c</a> <a href="#cite_ref-pabr5b_56-3">d</a> <a href="#cite_ref-pabr5b_56-4">e</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrownPetcherSmith1968" class="citation journal cs1">Brown, D.; Petcher, T. J.; Smith, A. J. (1968). "Crystal Structures of some Protactinium Bromides". <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. 217 (5130): 737. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1968Natur.217..737B">1968Natur.217..737B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F217737a0">10.1038/217737a0</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4264482">4264482</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Crystal+Structures+of+some+Protactinium+Bromides&rft.volume=217&rft.issue=5130&rft.pages=737&rft.date=1968&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4264482%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2F217737a0&rft_id=info%3Abibcode%2F1968Natur.217..737B&rft.aulast=Brown&rft.aufirst=D.&rft.au=Petcher%2C+T.+J.&rft.au=Smith%2C+A.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-pacl5-57">^ <a href="#cite_ref-pacl5_57-0">a</a> <a href="#cite_ref-pacl5_57-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDodgeSmithJohnsonElson1967" class="citation journal cs1">Dodge, R. P.; Smith, G. S.; Johnson, Q.; Elson, R. E. (1967). "The crystal structure of protactinium pentachloride". <a href="/wiki/Acta_Crystallographica" title="Acta Crystallographica">Acta Crystallographica</a>. 22 (1): 85–89. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1967AcCry..22...85D">1967AcCry..22...85D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS0365110X67000155">10.1107/S0365110X67000155</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica&rft.atitle=The+crystal+structure+of+protactinium+pentachloride&rft.volume=22&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E85-%3C%2Fspan%3E89&rft.date=1967&rft_id=info%3Adoi%2F10.1107%2FS0365110X67000155&rft_id=info%3Abibcode%2F1967AcCry..22...85D&rft.aulast=Dodge&rft.aufirst=R.+P.&rft.au=Smith%2C+G.+S.&rft.au=Johnson%2C+Q.&rft.au=Elson%2C+R.+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-pabr5-58">^ <a href="#cite_ref-pabr5_58-0">a</a> <a href="#cite_ref-pabr5_58-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrownPetcherSmith1969" class="citation journal cs1">Brown, D.; Petcher, T. J.; Smith, A. J. (1969). "The crystal structure of β-protactinium pentabromide". <a href="/wiki/Acta_Crystallographica_B" class="mw-redirect" title="Acta Crystallographica B">Acta Crystallographica B</a>. 25 (2): 178. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1969AcCrB..25..178B">1969AcCrB..25..178B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS0567740869007357">10.1107/S0567740869007357</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica+B&rft.atitle=The+crystal+structure+of+%CE%B2-protactinium+pentabromide&rft.volume=25&rft.issue=2&rft.pages=178&rft.date=1969&rft_id=info%3Adoi%2F10.1107%2FS0567740869007357&rft_id=info%3Abibcode%2F1969AcCrB..25..178B&rft.aulast=Brown&rft.aufirst=D.&rft.au=Petcher%2C+T.+J.&rft.au=Smith%2C+A.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-papo3-59">^ <a href="#cite_ref-papo3_59-0">a</a> <a href="#cite_ref-papo3_59-1">b</a> <a href="#cite_ref-papo3_59-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrandelDacheux2004" class="citation journal cs1">Brandel, V.; Dacheux, N. (2004). "Chemistry of tetravalent actinide phosphates—Part I". <a href="/wiki/Journal_of_Solid_State_Chemistry" title="Journal of Solid State Chemistry">Journal of Solid State Chemistry</a>. 177 (12): 4743. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004JSSCh.177.4743B">2004JSSCh.177.4743B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jssc.2004.08.009">10.1016/j.jssc.2004.08.009</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Solid+State+Chemistry&rft.atitle=Chemistry+of+tetravalent+actinide+phosphates%E2%80%94Part+I&rft.volume=177&rft.issue=12&rft.pages=4743&rft.date=2004&rft_id=info%3Adoi%2F10.1016%2Fj.jssc.2004.08.009&rft_id=info%3Abibcode%2F2004JSSCh.177.4743B&rft.aulast=Brandel&rft.aufirst=V.&rft.au=Dacheux%2C+N.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-cene-60">^ <a href="#cite_ref-cene_60-0">a</a> <a href="#cite_ref-cene_60-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStarksParsonsStreitwieserEdelstein1974" class="citation journal cs1">Starks, David F.; Parsons, Thomas C.; <a href="/wiki/Andrew_Streitwieser" title="Andrew Streitwieser">Streitwieser, Andrew</a>; Edelstein, Norman (1974). "Bis(π-cyclooctatetraene) protactinium". <a href="/wiki/Inorganic_Chemistry_(journal)" title="Inorganic Chemistry (journal)">Inorganic Chemistry</a>. 13 (6): 1307. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fic50136a011">10.1021/ic50136a011</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Inorganic+Chemistry&rft.atitle=Bis%28%CF%80-cyclooctatetraene%29+protactinium&rft.volume=13&rft.issue=6&rft.pages=1307&rft.date=1974&rft_id=info%3Adoi%2F10.1021%2Fic50136a011&rft.aulast=Starks&rft.aufirst=David+F.&rft.au=Parsons%2C+Thomas+C.&rft.au=Streitwieser%2C+Andrew&rft.au=Edelstein%2C+Norman&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1268-61"><a href="#cite_ref-g1268_61-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1268 </li> <li id="cite_note-pacl4b-62">^ <a href="#cite_ref-pacl4b_62-0">a</a> <a href="#cite_ref-pacl4b_62-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFElsonFriedSellersZachariasen1950" class="citation journal cs1">Elson, R.; Fried, Sherman; Sellers, Philip; Zachariasen, W. H. (1950). "The tetravalent and pentavalent states of protactinium". <a href="/wiki/Journal_of_the_American_Chemical_Society" title="Journal of the American Chemical Society">Journal of the American Chemical Society</a>. 72 (12): 5791. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1950JAChS..72.5791E">1950JAChS..72.5791E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fja01168a547">10.1021/ja01168a547</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+American+Chemical+Society&rft.atitle=The+tetravalent+and+pentavalent+states+of+protactinium&rft.volume=72&rft.issue=12&rft.pages=5791&rft.date=1950&rft_id=info%3Adoi%2F10.1021%2Fja01168a547&rft_id=info%3Abibcode%2F1950JAChS..72.5791E&rft.aulast=Elson&rft.aufirst=R.&rft.au=Fried%2C+Sherman&rft.au=Sellers%2C+Philip&rft.au=Zachariasen%2C+W.+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1269-63"><a href="#cite_ref-g1269_63-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1269 </li> <li id="cite_note-64"><a href="#cite_ref-64">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIyerSmith1971" class="citation journal cs1">Iyer, P. N.; Smith, A. J. (1971). "Double oxides containing niobium, tantalum or protactinium. IV. Further systems involving alkali metals". <a href="/wiki/Acta_Crystallographica_B" class="mw-redirect" title="Acta Crystallographica B">Acta Crystallographica B</a>. 27 (4): 731. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1971AcCrB..27..731I">1971AcCrB..27..731I</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS056774087100284X">10.1107/S056774087100284X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica+B&rft.atitle=Double+oxides+containing+niobium%2C+tantalum+or+protactinium.+IV.+Further+systems+involving+alkali+metals&rft.volume=27&rft.issue=4&rft.pages=731&rft.date=1971&rft_id=info%3Adoi%2F10.1107%2FS056774087100284X&rft_id=info%3Abibcode%2F1971AcCrB..27..731I&rft.aulast=Iyer&rft.aufirst=P.+N.&rft.au=Smith%2C+A.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-65"><a href="#cite_ref-65">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIyerSmith1967" class="citation journal cs1">Iyer, P. N.; Smith, A. J. (1967). "Double oxides containing niobium, tantalum, or protactinium. III. Systems involving the rare earths". <a href="/wiki/Acta_Crystallographica" title="Acta Crystallographica">Acta Crystallographica</a>. 23 (5): 740. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1967AcCry..23..740I">1967AcCry..23..740I</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1107%2FS0365110X67003639">10.1107/S0365110X67003639</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Crystallographica&rft.atitle=Double+oxides+containing+niobium%2C+tantalum%2C+or+protactinium.+III.+Systems+involving+the+rare+earths&rft.volume=23&rft.issue=5&rft.pages=740&rft.date=1967&rft_id=info%3Adoi%2F10.1107%2FS0365110X67003639&rft_id=info%3Abibcode%2F1967AcCry..23..740I&rft.aulast=Iyer&rft.aufirst=P.+N.&rft.au=Smith%2C+A.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-target-66">^ <a href="#cite_ref-target_66-0">a</a> <a href="#cite_ref-target_66-1">b</a> <a href="#cite_ref-target_66-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrossmannMaierSzerypoFriebel2008" class="citation journal cs1">Grossmann, R.; Maier, H.; Szerypo, J.; Friebel, H. (2008). "Preparation of 231Pa targets". <a href="/wiki/Nuclear_Instruments_and_Methods_in_Physics_Research_A" class="mw-redirect" title="Nuclear Instruments and Methods in Physics Research A">Nuclear Instruments and Methods in Physics Research A</a>. 590 (1–3): 122. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2008NIMPA.590..122G">2008NIMPA.590..122G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.nima.2008.02.084">10.1016/j.nima.2008.02.084</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nuclear+Instruments+and+Methods+in+Physics+Research+A&rft.atitle=Preparation+of+231Pa+targets&rft.volume=590&rft.issue=%3Cspan+class%3D%22nowrap%22%3E1%E2%80%93%3C%2Fspan%3E3&rft.pages=122&rft.date=2008&rft_id=info%3Adoi%2F10.1016%2Fj.nima.2008.02.084&rft_id=info%3Abibcode%2F2008NIMPA.590..122G&rft.aulast=Grossmann&rft.aufirst=R.&rft.au=Maier%2C+H.&rft.au=Szerypo%2C+J.&rft.au=Friebel%2C+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-g1270-67"><a href="#cite_ref-g1270_67-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1270 </li> <li id="cite_note-g1271-68">^ <a href="#cite_ref-g1271_68-0">a</a> <a href="#cite_ref-g1271_68-1">b</a> <a href="#cite_ref-g1271_68-2">c</a> <a href="#Greenwood">Greenwood</a>, p. 1271 </li> <li id="cite_note-g1277-69"><a href="#cite_ref-g1277_69-0">^</a> <a href="#Greenwood">Greenwood</a>, p. 1277 </li> <li id="cite_note-g1278-70"><a href="#cite_ref-g1278_70-0">^</a> <a href="#Greenwood">Greenwood</a>, pp. 1278–1279 </li> <li id="cite_note-71"><a href="#cite_ref-71">^</a> Seifritz, Walter (1984) Nukleare Sprengkörper – Bedrohung oder Energieversorgung für die Menschheit, Thiemig-Verlag, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/3-521-06143-4" title="Special:BookSources/3-521-06143-4">3-521-06143-4</a>. </li> <li id="cite_note-72"><a href="#cite_ref-72">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGanesan,_S.1999" class="citation journal cs1">Ganesan, S. (1999). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160303231501/http://www.iisc.ernet.in/currsci/sept10/researcharticle.pdf">"A Re-calculation of Criticality Property of 231Pa Using New Nuclear Data"</a> (PDF). <a href="/wiki/Current_Science" title="Current Science">Current Science</a>. 77 (5): 667–677. Archived from <a rel="nofollow" class="external text" href="http://www.iisc.ernet.in/currsci/sept10/researcharticle.pdf">the original</a> (PDF) on 3 March 2016. Retrieved 21 March 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Current+Science&rft.atitle=A+Re-calculation+of+Criticality+Property+of+%3Csup%3E231%3C%2Fsup%3EPa+Using+New+Nuclear+Data&rft.volume=77&rft.issue=5&rft.pages=%3Cspan+class%3D%22nowrap%22%3E667-%3C%2Fspan%3E677&rft.date=1999&rft.au=Ganesan%2C+S.&rft_id=http%3A%2F%2Fwww.iisc.ernet.in%2Fcurrsci%2Fsept10%2Fresearcharticle.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-73"><a href="#cite_ref-73">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcManus,_J._F.Francois,_R.Gherardi,_J.-M.Keigwin,_L._D.2004" class="citation journal cs1">McManus, J. F.; Francois, R.; Gherardi, J.-M.; Keigwin, L. D.; et al. (2004). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130410051109/http://www.seas.harvard.edu/climate/pdf/mcmanus-2004.pdf">"Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes"</a> (PDF). <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. 428 (6985): 834–837. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004Natur.428..834M">2004Natur.428..834M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature02494">10.1038/nature02494</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15103371">15103371</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:205210064">205210064</a>. Archived from <a rel="nofollow" class="external text" href="http://www.seas.harvard.edu/climate/pdf/mcmanus-2004.pdf">the original</a> (PDF) on 10 April 2013. Retrieved 29 November 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Collapse+and+rapid+resumption+of+Atlantic+meridional+circulation+linked+to+deglacial+climate+changes&rft.volume=428&rft.issue=6985&rft.pages=%3Cspan+class%3D%22nowrap%22%3E834-%3C%2Fspan%3E837&rft.date=2004&rft_id=info%3Adoi%2F10.1038%2Fnature02494&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A205210064%23id-name%3DS2CID&rft_id=info%3Apmid%2F15103371&rft_id=info%3Abibcode%2F2004Natur.428..834M&rft.au=McManus%2C+J.+F.&rft.au=Francois%2C+R.&rft.au=Gherardi%2C+J.-M.&rft.au=Keigwin%2C+L.+D.&rft.au=Brown-Leger%2C+S.&rft_id=http%3A%2F%2Fwww.seas.harvard.edu%2Fclimate%2Fpdf%2Fmcmanus-2004.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-74"><a href="#cite_ref-74">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChengEdwardsMurrellBenjamin1998" class="citation journal cs1">Cheng, H.; Edwards, R.Lawrence; Murrell, M. T.; Benjamin, T. M. (1998). "Uranium-thorium-protactinium dating systematics". <a href="/wiki/Geochimica_et_Cosmochimica_Acta" title="Geochimica et Cosmochimica Acta">Geochimica et Cosmochimica Acta</a>. 62 (21–22): 3437. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1998GeCoA..62.3437C">1998GeCoA..62.3437C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FS0016-7037%2898%2900255-5">10.1016/S0016-7037(98)00255-5</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Geochimica+et+Cosmochimica+Acta&rft.atitle=Uranium-thorium-protactinium+dating+systematics&rft.volume=62&rft.issue=%3Cspan+class%3D%22nowrap%22%3E21%E2%80%93%3C%2Fspan%3E22&rft.pages=3437&rft.date=1998&rft_id=info%3Adoi%2F10.1016%2FS0016-7037%2898%2900255-5&rft_id=info%3Abibcode%2F1998GeCoA..62.3437C&rft.aulast=Cheng&rft.aufirst=H.&rft.au=Edwards%2C+R.Lawrence&rft.au=Murrell%2C+M.+T.&rft.au=Benjamin%2C+T.+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> <li id="cite_note-75"><a href="#cite_ref-75">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPalshin,_E.S.1968" class="citation book cs1">Palshin, E.S.; et al. (1968). Analytical chemistry of protactinium. Moscow: Nauka.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Analytical+chemistry+of+protactinium&rft.place=Moscow&rft.pub=Nauka&rft.date=1968&rft.au=Palshin%2C+E.S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Bibliography">Bibliography</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=18" title="Edit section: Bibliography">edit</a>]</div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="Greenwood" class="citation book cs1"><a href="/wiki/Norman_Greenwood" title="Norman Greenwood">Greenwood, Norman N.</a>; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). <a href="/wiki/Butterworth%E2%80%93Heinemann" class="mw-redirect" title="Butterworth–Heinemann">Butterworth–Heinemann</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0080379418" title="Special:BookSources/978-0080379418"><bdi>978-0080379418</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemistry+of+the+Elements&rft.edition=2nd&rft.pub=Butterworth%E2%80%93Heinemann&rft.date=1997&rft.isbn=978-0080379418&rft.aulast=Greenwood&rft.aufirst=Norman+N.&rft.au=Earnshaw%2C+Alan&rfr_id=info%3Asid%2Fen.wikipedia.org%3AProtactinium" class="Z3988"></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2>[<a href="/w/index.php?title=Protactinium&action=edit&section=19" title="Edit section: External links">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-flex"> <div class="side-box-image"><a href="/wiki/File:Commons-logo.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/45px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/59px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <a href="https://commons.wikimedia.org/wiki/Protactinium" class="extiw" title="commons:Protactinium">Protactinium</a>.</div></div> </div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1235681985"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1237033735"><div class="side-box side-box-right plainlinks sistersitebox"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-flex"> <div class="side-box-image"><a href="/wiki/File:Wiktionary-logo-en-v2.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/40px-Wiktionary-logo-en-v2.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/60px-Wiktionary-logo-en-v2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/80px-Wiktionary-logo-en-v2.svg.png 2x" data-file-width="512" data-file-height="512" /></a></div> <div class="side-box-text plainlist">Look up <a href="https://en.wiktionary.org/wiki/protactinium" class="extiw" title="wiktionary:protactinium">protactinium</a> in Wiktionary, the free dictionary.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="http://www.periodicvideos.com/videos/091.htm">Protactinium</a> at <a href="/wiki/The_Periodic_Table_of_Videos" class="mw-redirect" title="The Periodic Table of Videos">The Periodic Table of Videos</a> (University of Nottingham)</li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Periodic_table18" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Periodic_table_(navbox)" title="Template:Periodic table (navbox)"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Periodic_table_(navbox)" title="Template talk:Periodic table (navbox)"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Periodic_table_(navbox)" title="Special:EditPage/Template:Periodic table (navbox)"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Periodic_table18" style="font-size:114%;margin:0 4em"><a href="/wiki/Periodic_table" title="Periodic table">Periodic table</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd wraplinks" style="width:100%;padding:0"><div style="padding:0 0.25em"> <table style="table-layout:fixed; width:100%;" aria-describedby="periodic-table-legend"> <tbody><tr> <td style="line-height:100%;"> </td> <th scope="col" style="font-weight:normal;"><a href="/wiki/Alkali_metal" title="Alkali metal">1</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Alkaline_earth_metal" title="Alkaline earth metal">2</a> </th> <td colspan="14"> </td> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_3_element" title="Group 3 element">3</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_4_element" title="Group 4 element">4</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_5_element" title="Group 5 element">5</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_6_element" title="Group 6 element">6</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_7_element" title="Group 7 element">7</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_8_element" title="Group 8 element">8</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_9_element" title="Group 9 element">9</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_10_element" title="Group 10 element">10</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_11_element" title="Group 11 element">11</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Group_12_element" title="Group 12 element">12</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Boron_group" title="Boron group">13</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Carbon_group" title="Carbon group">14</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Pnictogen" title="Pnictogen">15</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Chalcogen" title="Chalcogen">16</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Halogen" title="Halogen">17</a> </th> <th scope="col" style="font-weight:normal;"><a href="/wiki/Noble_gas" title="Noble gas">18</a> </th></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_1_element" title="Period 1 element">1</a> </th> <td title="H, Hydrogen" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Hydrogen" title="Hydrogen">H</a> </td> <td colspan="30"> </td> <td title="He, Helium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Helium" title="Helium">He</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_2_element" title="Period 2 element">2</a> </th> <td title="Li, Lithium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Lithium" title="Lithium">Li</a> </td> <td title="Be, Beryllium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Beryllium" title="Beryllium">Be</a> </td> <td colspan="24"> </td> <td title="B, Boron" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Boron" title="Boron">B</a> </td> <td title="C, Carbon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Carbon" title="Carbon">C</a> </td> <td title="N, Nitrogen" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Nitrogen" title="Nitrogen">N</a> </td> <td title="O, Oxygen" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Oxygen" title="Oxygen">O</a> </td> <td title="F, Fluorine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Fluorine" title="Fluorine">F</a> </td> <td title="Ne, Neon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Neon" title="Neon">Ne</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_3_element" title="Period 3 element">3</a> </th> <td title="Na, Sodium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Sodium" title="Sodium">Na</a> </td> <td title="Mg, Magnesium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Magnesium" title="Magnesium">Mg</a> </td> <td colspan="24"> </td> <td title="Al, Aluminium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Aluminium" title="Aluminium">Al</a> </td> <td title="Si, Silicon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Silicon" title="Silicon">Si</a> </td> <td title="P, Phosphorus" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Phosphorus" title="Phosphorus">P</a> </td> <td title="S, Sulfur" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Sulfur" title="Sulfur">S</a> </td> <td title="Cl, Chlorine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Chlorine" title="Chlorine">Cl</a> </td> <td title="Ar, Argon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Argon" title="Argon">Ar</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_4_element" title="Period 4 element">4</a> </th> <td title="K, Potassium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Potassium" title="Potassium">K</a> </td> <td title="Ca, Calcium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Calcium" title="Calcium">Ca</a> </td> <td colspan="14"> </td> <td title="Sc, Scandium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Scandium" title="Scandium">Sc</a> </td> <td title="Ti, Titanium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Titanium" title="Titanium">Ti</a> </td> <td title="V, Vanadium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Vanadium" title="Vanadium">V</a> </td> <td title="Cr, Chromium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Chromium" title="Chromium">Cr</a> </td> <td title="Mn, Manganese" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Manganese" title="Manganese">Mn</a> </td> <td title="Fe, Iron" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Iron" title="Iron">Fe</a> </td> <td title="Co, Cobalt" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Cobalt" title="Cobalt">Co</a> </td> <td title="Ni, Nickel" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Nickel" title="Nickel">Ni</a> </td> <td title="Cu, Copper" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Copper" title="Copper">Cu</a> </td> <td title="Zn, Zinc" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Zinc" title="Zinc">Zn</a> </td> <td title="Ga, Gallium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Gallium" title="Gallium">Ga</a> </td> <td title="Ge, Germanium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Germanium" title="Germanium">Ge</a> </td> <td title="As, Arsenic" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Arsenic" title="Arsenic">As</a> </td> <td title="Se, Selenium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Selenium" title="Selenium">Se</a> </td> <td title="Br, Bromine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Bromine" title="Bromine">Br</a> </td> <td title="Kr, Krypton" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Krypton" title="Krypton">Kr</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_5_element" title="Period 5 element">5</a> </th> <td title="Rb, Rubidium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Rubidium" title="Rubidium">Rb</a> </td> <td title="Sr, Strontium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Strontium" title="Strontium">Sr</a> </td> <td colspan="14"> </td> <td title="Y, Yttrium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Yttrium" title="Yttrium">Y</a> </td> <td title="Zr, Zirconium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Zirconium" title="Zirconium">Zr</a> </td> <td title="Nb, Niobium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Niobium" title="Niobium">Nb</a> </td> <td title="Mo, Molybdenum" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Molybdenum" title="Molybdenum">Mo</a> </td> <td title="Tc, Technetium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Technetium" title="Technetium">Tc</a> </td> <td title="Ru, Ruthenium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Ruthenium" title="Ruthenium">Ru</a> </td> <td title="Rh, Rhodium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Rhodium" title="Rhodium">Rh</a> </td> <td title="Pd, Palladium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Palladium" title="Palladium">Pd</a> </td> <td title="Ag, Silver" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Silver" title="Silver">Ag</a> </td> <td title="Cd, Cadmium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Cadmium" title="Cadmium">Cd</a> </td> <td title="In, Indium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Indium" title="Indium">In</a> </td> <td title="Sn, Tin" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Tin" title="Tin">Sn</a> </td> <td title="Sb, Antimony" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Antimony" title="Antimony">Sb</a> </td> <td title="Te, Tellurium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Tellurium" title="Tellurium">Te</a> </td> <td title="I, Iodine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Iodine" title="Iodine">I</a> </td> <td title="Xe, Xenon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Xenon" title="Xenon">Xe</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_6_element" title="Period 6 element">6</a> </th> <td title="Cs, Caesium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Caesium" title="Caesium">Cs</a> </td> <td title="Ba, Barium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Barium" title="Barium">Ba</a> </td> <td title="La, Lanthanum" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Lanthanum" title="Lanthanum">La</a> </td> <td title="Ce, Cerium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Cerium" title="Cerium">Ce</a> </td> <td title="Pr, Praseodymium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Praseodymium" title="Praseodymium">Pr</a> </td> <td title="Nd, Neodymium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Neodymium" title="Neodymium">Nd</a> </td> <td title="Pm, Promethium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Promethium" title="Promethium">Pm</a> </td> <td title="Sm, Samarium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Samarium" title="Samarium">Sm</a> </td> <td title="Eu, Europium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Europium" title="Europium">Eu</a> </td> <td title="Gd, Gadolinium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Gadolinium" title="Gadolinium">Gd</a> </td> <td title="Tb, Terbium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Terbium" title="Terbium">Tb</a> </td> <td title="Dy, Dysprosium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Dysprosium" title="Dysprosium">Dy</a> </td> <td title="Ho, Holmium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Holmium" title="Holmium">Ho</a> </td> <td title="Er, Erbium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Erbium" title="Erbium">Er</a> </td> <td title="Tm, Thulium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Thulium" title="Thulium">Tm</a> </td> <td title="Yb, Ytterbium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Ytterbium" title="Ytterbium">Yb</a> </td> <td title="Lu, Lutetium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Lutetium" title="Lutetium">Lu</a> </td> <td title="Hf, Hafnium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Hafnium" title="Hafnium">Hf</a> </td> <td title="Ta, Tantalum" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Tantalum" title="Tantalum">Ta</a> </td> <td title="W, Tungsten" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Tungsten" title="Tungsten">W</a> </td> <td title="Re, Rhenium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Rhenium" title="Rhenium">Re</a> </td> <td title="Os, Osmium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Osmium" title="Osmium">Os</a> </td> <td title="Ir, Iridium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Iridium" title="Iridium">Ir</a> </td> <td title="Pt, Platinum" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Platinum" title="Platinum">Pt</a> </td> <td title="Au, Gold" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Gold" title="Gold">Au</a> </td> <td title="Hg, Mercury" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Mercury_(element)" title="Mercury (element)">Hg</a> </td> <td title="Tl, Thallium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Thallium" title="Thallium">Tl</a> </td> <td title="Pb, Lead" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Lead" title="Lead">Pb</a> </td> <td title="Bi, Bismuth" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Bismuth" title="Bismuth">Bi</a> </td> <td title="Po, Polonium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Polonium" title="Polonium">Po</a> </td> <td title="At, Astatine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Astatine" title="Astatine">At</a> </td> <td title="Rn, Radon" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Radon" title="Radon">Rn</a> </td></tr> <tr> <th scope="row" style="font-weight:normal;"><a href="/wiki/Period_7_element" title="Period 7 element">7</a> </th> <td title="Fr, Francium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Francium" title="Francium">Fr</a> </td> <td title="Ra, Radium" style="text-align:center; background-color:#ff9999; color:inherit; border:none; ;"><a href="/wiki/Radium" title="Radium">Ra</a> </td> <td title="Ac, Actinium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Actinium" title="Actinium">Ac</a> </td> <td title="Th, Thorium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Thorium" title="Thorium">Th</a> </td> <td title="Pa, Protactinium" style="text-align:center; background-color:#9bff99; color:inherit; border:3px solid black; ;"><a class="mw-selflink selflink">Pa</a> </td> <td title="U, Uranium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Uranium" title="Uranium">U</a> </td> <td title="Np, Neptunium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Neptunium" title="Neptunium">Np</a> </td> <td title="Pu, Plutonium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Plutonium" title="Plutonium">Pu</a> </td> <td title="Am, Americium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Americium" title="Americium">Am</a> </td> <td title="Cm, Curium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Curium" title="Curium">Cm</a> </td> <td title="Bk, Berkelium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Berkelium" title="Berkelium">Bk</a> </td> <td title="Cf, Californium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Californium" title="Californium">Cf</a> </td> <td title="Es, Einsteinium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Einsteinium" title="Einsteinium">Es</a> </td> <td title="Fm, Fermium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Fermium" title="Fermium">Fm</a> </td> <td title="Md, Mendelevium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Mendelevium" title="Mendelevium">Md</a> </td> <td title="No, Nobelium" style="text-align:center; background-color:#9bff99; color:inherit; border:none; ;"><a href="/wiki/Nobelium" title="Nobelium">No</a> </td> <td title="Lr, Lawrencium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Lawrencium" title="Lawrencium">Lr</a> </td> <td title="Rf, Rutherfordium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Rutherfordium" title="Rutherfordium">Rf</a> </td> <td title="Db, Dubnium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Dubnium" title="Dubnium">Db</a> </td> <td title="Sg, Seaborgium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Seaborgium" title="Seaborgium">Sg</a> </td> <td title="Bh, Bohrium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Bohrium" title="Bohrium">Bh</a> </td> <td title="Hs, Hassium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Hassium" title="Hassium">Hs</a> </td> <td title="Mt, Meitnerium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Meitnerium" title="Meitnerium">Mt</a> </td> <td title="Ds, Darmstadtium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Darmstadtium" title="Darmstadtium">Ds</a> </td> <td title="Rg, Roentgenium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Roentgenium" title="Roentgenium">Rg</a> </td> <td title="Cn, Copernicium" style="text-align:center; background-color:#99ccff; color:inherit; border:none; ;"><a href="/wiki/Copernicium" title="Copernicium">Cn</a> </td> <td title="Nh, Nihonium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Nihonium" title="Nihonium">Nh</a> </td> <td title="Fl, Flerovium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Flerovium" title="Flerovium">Fl</a> </td> <td title="Mc, Moscovium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Moscovium" title="Moscovium">Mc</a> </td> <td title="Lv, Livermorium" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Livermorium" title="Livermorium">Lv</a> </td> <td title="Ts, Tennessine" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Tennessine" title="Tennessine">Ts</a> </td> <td title="Og, Oganesson" style="text-align:center; background-color:#fdff8c; color:inherit; border:none; ;"><a href="/wiki/Oganesson" title="Oganesson">Og</a> </td></tr></tbody></table> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-even wraplinks" style="width:100%;padding:0"><div style="padding:0 0.25em"><div role="presentation" id="periodic-table-legend" style="border: 1px solid #a2a9b1; width:100%; line-height:120%; text-align:center; vertical-align:top; background:#f8f8f8;color:inherit; margin:0; margin:0;"><div style="padding:0.3em;"> <table style="width:100%; line-height:1.2em; table-layout:fixed; overflow:hidden; text-align:center;"> <tbody><tr> <td style="padding:0 1px; background:#ff9999;color:inherit;"><a href="/wiki/S-block" class="mw-redirect" title="S-block">s-block</a> </td> <td style="padding:0 1px; background:#9bff99;color:inherit;"><a href="/wiki/F-block" class="mw-redirect" title="F-block">f-block</a> </td> <td style="padding:0 1px; background:#99ccff;color:inherit;"><a href="/wiki/D-block" class="mw-redirect" title="D-block">d-block</a> </td> <td style="padding:0 1px; background:#fdff8c;color:inherit;"><a href="/wiki/P-block" class="mw-redirect" title="P-block">p-block</a> </td></tr></tbody></table> </div> </div></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Protactinium_compounds50" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Protactinium_compounds" title="Template:Protactinium compounds"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Protactinium_compounds" title="Template talk:Protactinium compounds"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Protactinium_compounds" title="Special:EditPage/Template:Protactinium compounds"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Protactinium_compounds50" style="font-size:114%;margin:0 4em"><a href="/wiki/Protactinium_compounds" title="Protactinium compounds">Protactinium compounds</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pa(II)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Protactinium_monoxide" title="Protactinium monoxide">PaO</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pa(III)</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Protactinium_trihydride" title="Protactinium trihydride">PaH3</a></li> <li><a href="/wiki/Protactinium_nitride" title="Protactinium nitride">PaN</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pa(IV)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Protactinium(IV)_oxide" title="Protactinium(IV) oxide">PaO2</a></li> <li><a href="/wiki/Protactinium(IV)_chloride" title="Protactinium(IV) chloride">PaCl4</a></li> <li><a href="/wiki/Protactinium(IV)_bromide" title="Protactinium(IV) bromide">PaBr4</a></li> <li><a href="/wiki/Protactinium(IV)_fluoride" class="mw-redirect" title="Protactinium(IV) fluoride">PaF4</a></li> <li><a href="/wiki/Protactinium_tetraiodide" title="Protactinium tetraiodide">PaI4</a></li> <li><a href="/w/index.php?title=Protactinium(IV)_oxychloride&action=edit&redlink=1" class="new" title="Protactinium(IV) oxychloride (page does not exist)">PaOCl2</a></li> <li><a href="/w/index.php?title=Protactinium(IV)_carbide&action=edit&redlink=1" class="new" title="Protactinium(IV) carbide (page does not exist)">PaC</a></li> <li><a href="/wiki/Protactinocene" class="mw-redirect" title="Protactinocene">Pa(C8H8)2</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pa(V)</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Protactinium(V)_oxide" title="Protactinium(V) oxide">Pa2O5</a></li> <li><a href="/wiki/Protactinium(V)_fluoride" title="Protactinium(V) fluoride">PaF5</a></li> <li><a href="/wiki/Protactinium(V)_chloride" title="Protactinium(V) chloride">PaCl5</a></li> <li><a href="/wiki/Protactinium(V)_bromide" title="Protactinium(V) bromide">PaBr5</a></li> <li><a href="/wiki/Protactinium(V)_iodide" title="Protactinium(V) iodide">PaI5</a></li> <li><a href="/w/index.php?title=Protactinium(V)_dioxyfluoride&action=edit&redlink=1" class="new" title="Protactinium(V) dioxyfluoride (page does not exist)">PaO2F</a></li> <li><a href="/w/index.php?title=Protactinium(V)_dioxychloride&action=edit&redlink=1" class="new" title="Protactinium(V) dioxychloride (page does not exist)">PaO2Cl</a></li> <li><a href="/w/index.php?title=Protactinium(V)_dioxyiodide&action=edit&redlink=1" class="new" title="Protactinium(V) dioxyiodide (page does not exist)">PaO2I</a></li> <li><a href="/wiki/Protactinium(V)_oxynitrate" class="mw-redirect" title="Protactinium(V) oxynitrate">PaO(NO3)3</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox authority-control" aria-label="Navbox578" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <a href="https://www.wikidata.org/wiki/Q1109#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4175981-3">Germany</a></li><li><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/sh85107634">United States</a></li><li><a rel="nofollow" class="external text" href="https://www.nli.org.il/en/authorities/987007541390005171">Israel</a></li></ul></div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Protactinium&oldid=1274596214">https://en.wikipedia.org/w/index.php?title=Protactinium&oldid=1274596214</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Protactinium" title="Category:Protactinium">Protactinium</a></li><li><a href="/wiki/Category:Chemical_elements" title="Category:Chemical elements">Chemical elements</a></li><li><a href="/wiki/Category:Chemical_elements_with_body-centered_tetragonal_structure" title="Category:Chemical elements with body-centered tetragonal structure">Chemical elements with body-centered tetragonal structure</a></li><li><a href="/wiki/Category:Actinides" title="Category:Actinides">Actinides</a></li><li><a href="/wiki/Category:Chemical_elements_predicted_by_Dmitri_Mendeleev" title="Category:Chemical elements predicted by Dmitri Mendeleev">Chemical elements predicted by Dmitri Mendeleev</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Webarchive_template_wayback_links" title="Category:Webarchive template wayback links">Webarchive template wayback links</a></li><li><a href="/wiki/Category:Use_dmy_dates_from_February_2021" title="Category:Use dmy dates from February 2021">Use dmy dates from February 2021</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Articles_containing_Greek-language_text" title="Category:Articles containing Greek-language text">Articles containing Greek-language text</a></li><li><a href="/wiki/Category:Commons_link_is_on_Wikidata" title="Category:Commons link is on Wikidata">Commons link is on Wikidata</a></li><li><a href="/wiki/Category:Good_articles" title="Category:Good articles">Good articles</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 8 February 2025, at 07:17 (UTC).</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Protactinium&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" lang="en" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"> Search </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" >Protactinium</div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"> 134 languages </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"> Add topic </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-56d8db5f6f-7t9nq","wgBackendResponseTime":134,"wgPageParseReport":{"limitreport":{"cputime":"2.368","walltime":"2.920","ppvisitednodes":{"value":42962,"limit":1000000},"postexpandincludesize":{"value":623932,"limit":2097152},"templateargumentsize":{"value":47850,"limit":2097152},"expansiondepth":{"value":56,"limit":100},"expensivefunctioncount":{"value":6,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":277001,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 2625.508 1 -total"," 74.03% 1943.537 3 Template:Infobox"," 53.64% 1408.202 1 Template:Infobox_protactinium"," 53.48% 1404.092 1 Template:Infobox_element"," 19.03% 499.623 144 Template:Trim"," 18.58% 487.901 1 Template:Infobox_protactinium_isotopes"," 18.38% 482.535 1 Template:Infobox_isotopes_(meta)"," 17.79% 467.007 1 Template:Isotopes/main/table"," 16.90% 443.629 1 Template:Reflist"," 16.45% 431.986 7 Template:Isotopes/main/isotope"]},"scribunto":{"limitreport-timeusage":{"value":"1.218","limit":"10.000"},"limitreport-memusage":{"value":20582504,"limit":52428800},"limitreport-profile":[["?","740","40.2"],["MediaWiki\\Extension\\Scribunto\\Engines\\LuaSandbox\\LuaSandboxCallback::getExpandedArgument","160","8.7"],["MediaWiki\\Extension\\Scribunto\\Engines\\LuaSandbox\\LuaSandboxCallback::callParserFunction","140","7.6"],["recursiveClone \u003CmwInit.lua:45\u003E","140","7.6"],["MediaWiki\\Extension\\Scribunto\\Engines\\LuaSandbox\\LuaSandboxCallback::match","80","4.3"],["\u003Cmw.lua:694\u003E","60","3.3"],["insert","60","3.3"],["MediaWiki\\Extension\\Scribunto\\Engines\\LuaSandbox\\LuaSandboxCallback::getAllExpandedArguments","60","3.3"],["dataWrapper \u003Cmw.lua:672\u003E","60","3.3"],["type","40","2.2"],["[others]","300","16.3"]]},"cachereport":{"origin":"mw-web.eqiad.main-775cfc968-s2wzw","timestamp":"20250211195721","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Protactinium","url":"https:\/\/en.wikipedia.org\/wiki\/Protactinium","sameAs":"http:\/\/www.wikidata.org\/entity\/Q1109","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q1109","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2001-05-17T14:28:40Z","dateModified":"2025-02-08T07:17:54Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/e\/ea\/Protactinium_%28Element_-_91%29_2.jpg","headline":"element with symbol Pa and atomic number of 91"}</script> </body> </html>