CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-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-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Pyramidal carbocation - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-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-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":"cfc521be-3a84-4c4b-9ea7-4172aaa2cf6f","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Pyramidal_carbocation","wgTitle":"Pyramidal carbocation","wgCurRevisionId":1256121341,"wgRevisionId":1256121341,"wgArticleId":49668604,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Wikipedia articles that are too technical from February 2017","All articles that are too technical","Cations","Reactive intermediates"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Pyramidal_carbocation","wgRelevantArticleId":49668604,"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":30000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q23011489","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","mediawiki.page.gallery.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"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","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.quicksurveys.init","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</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.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cmediawiki.page.gallery.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.4"> <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/3/39/Pyramidal_ion_4_sided_with_numbers.jpg"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="748"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/3/39/Pyramidal_ion_4_sided_with_numbers.jpg"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="499"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="399"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Pyramidal carbocation - 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/Pyramidal_carbocation"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Pyramidal_carbocation&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/Pyramidal_carbocation"> <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-Pyramidal_carbocation rootpage-Pyramidal_carbocation 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" > <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" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </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"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></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"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></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"><span>Recent changes</span></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"><span>Upload file</span></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"> <span class="mw-logo-container skin-invert"> <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;"> </span> </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"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </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" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </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" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </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/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></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=Pyramidal+carbocation" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></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=Pyramidal+carbocation" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></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" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </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/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Pyramidal+carbocation" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Pyramidal+carbocation" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></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"><span>learn more</span></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"><span>Contributions</span></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"><span>Talk</span></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"> <span class="vector-toc-numb">1</span> <span>History</span> </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Theoretical_background" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Theoretical_background"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Theoretical background</span> </div> </a> <button aria-controls="toc-Theoretical_background-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Theoretical background subsection</span> </button> <ul id="toc-Theoretical_background-sublist" class="vector-toc-list"> <li id="toc-Apical_carbon_atom" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Apical_carbon_atom"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Apical carbon atom</span> </div> </a> <ul id="toc-Apical_carbon_atom-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Base_of_the_pyramid" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Base_of_the_pyramid"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Base of the pyramid</span> </div> </a> <ul id="toc-Base_of_the_pyramid-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Interaction_between_apex_and_base" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Interaction_between_apex_and_base"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Interaction between apex and base</span> </div> </a> <ul id="toc-Interaction_between_apex_and_base-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Examples" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Examples"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Examples</span> </div> </a> <button aria-controls="toc-Examples-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Examples subsection</span> </button> <ul id="toc-Examples-sublist" class="vector-toc-list"> <li id="toc-Monocation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Monocation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Monocation</span> </div> </a> <ul id="toc-Monocation-sublist" class="vector-toc-list"> <li id="toc-Reaction_with_methanol_and_benzoic_acid" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Reaction_with_methanol_and_benzoic_acid"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.1</span> <span>Reaction with methanol and benzoic acid</span> </div> </a> <ul id="toc-Reaction_with_methanol_and_benzoic_acid-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bishomomonocarbocation" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Bishomomonocarbocation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1.2</span> <span>Bishomomonocarbocation</span> </div> </a> <ul id="toc-Bishomomonocarbocation-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Dication" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Dication"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Dication</span> </div> </a> <ul id="toc-Dication-sublist" class="vector-toc-list"> <li id="toc-Reactions_of_the_dication" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Reactions_of_the_dication"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2.1</span> <span>Reactions of the dication</span> </div> </a> <ul id="toc-Reactions_of_the_dication-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_substitution_patterns_at_the_dications" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Other_substitution_patterns_at_the_dications"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2.2</span> <span>Other substitution patterns at the dications</span> </div> </a> <ul id="toc-Other_substitution_patterns_at_the_dications-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Tervalent_and_higher_ions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Tervalent_and_higher_ions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Tervalent and higher ions</span> </div> </a> <ul id="toc-Tervalent_and_higher_ions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Notes_and_references" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes_and_references"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Notes and references</span> </div> </a> <ul id="toc-Notes_and_references-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" > <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" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </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"><span class="mw-page-title-main">Pyramidal carbocation</span></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 2 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-2" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">2 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Piramidaal_carbokation" title="Piramidaal carbokation – Dutch" lang="nl" hreflang="nl" data-title="Piramidaal carbokation" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Carboc%C3%A1tion_piramidal" title="Carbocátion piramidal – Portuguese" lang="pt" hreflang="pt" data-title="Carbocátion piramidal" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q23011489#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></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/Pyramidal_carbocation" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Pyramidal_carbocation" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></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" ><span class="vector-dropdown-label-text">English</span> </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/Pyramidal_carbocation"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></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" ><span class="vector-dropdown-label-text">Tools</span> </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/Pyramidal_carbocation"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&action=history"><span>View history</span></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/Pyramidal_carbocation" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Pyramidal_carbocation" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></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"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&oldid=1256121341" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Pyramidal_carbocation&id=1256121341&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></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%2FPyramidal_carbocation"><span>Get shortened URL</span></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%2FPyramidal_carbocation"><span>Download QR code</span></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=Pyramidal_carbocation&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Pyramidal_carbocation&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></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 id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q23011489" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></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> <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"><style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Technical plainlinks metadata ambox ambox-style ambox-technical" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/60px-Edit-clear.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/80px-Edit-clear.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>may be too technical for most readers to understand</b>.<span class="hide-when-compact"> Please <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Pyramidal_carbocation&action=edit">help improve it</a> to <a href="/wiki/Wikipedia:Make_technical_articles_understandable" title="Wikipedia:Make technical articles understandable">make it understandable to non-experts</a>, without removing the technical details.</span> <span class="date-container"><i>(<span class="date">February 2017</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Pyramidal_ion_4_sided_with_numbers.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/220px-Pyramidal_ion_4_sided_with_numbers.jpg" decoding="async" width="220" height="137" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/330px-Pyramidal_ion_4_sided_with_numbers.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/3/39/Pyramidal_ion_4_sided_with_numbers.jpg 2x" data-file-width="401" data-file-height="250" /></a><figcaption>An example of the monovalent carbocation</figcaption></figure> <p>A <b>pyramidal carbocation</b> is a type of <a href="/wiki/Carbocation" title="Carbocation">carbocation</a> with a specific configuration. This ion exists as a third class, besides the classical and <a href="/wiki/Non-classical_ion" class="mw-redirect" title="Non-classical ion">non-classical ions</a>. In these ions, a single carbon atom hovers over a four- or five-sided <a href="/wiki/Polygon" title="Polygon">polygon</a>, in effect forming a <a href="/wiki/Pyramid" title="Pyramid">pyramid</a>. The four-sided pyramidal ion will carry a charge of 1+, and the five-sided pyramid will carry 2+. In the images (<i>at upper right)</i>, the black spot on the vertical line represents the hovering carbon atom. </p><p>The apparent coordination number of five, or even six, associated with the carbon atom at the top of the pyramid is a rarity as compared to the usual maximum of four. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Studying these cations was sparked, at the time, by amazing results in <a href="/wiki/Computational_chemistry" title="Computational chemistry">computational chemistry</a>. While calculating the optimal geometry of the mono-cation which arises from the extraction of chloride from 3-chlorotricyclo[2.1.0.0<sup>2,5</sup>]pentane, the three bridges were expected to orient in space with angles of roughly 120°. The calculations however showed the four-sided pyramid to be the most stable configuration. At the top of this pyramid, there resides a carbon atom, still connected to a hydrogen. The original expected structure turned out to be not even close to an energy minimum: it represented a maximum.<sup id="cite_ref-Stohrer_72_1-0" class="reference"><a href="#cite_note-Stohrer_72-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><b>Figure 1:</b> Several possibilities for (CH)<sub>5</sub> cation.</dd> <dd><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/33/Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg/500px-Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg" decoding="async" width="500" height="209" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/33/Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg/750px-Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/33/Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg/1000px-Pyramidal_ion_4_sided_Stohrer_and_Hoffmann.jpg 2x" data-file-width="1111" data-file-height="465" /></a></span></dd> <dd><b>1a</b> starting situation in the calculations: the chloride ion just left.</dd> <dd><b>1b</b> the expected structure. Charge has been delocalized over three carbon atoms</dd> <dd><b>1c</b> representation of the pyramidal ion.</dd></dl> <p>Depending on the method used, the ion <b>1c</b> in figure 1 is an absolute or just a relative minimum. </p> <div class="mw-heading mw-heading2"><h2 id="Theoretical_background">Theoretical background</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=2" title="Edit section: Theoretical background"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A complete theoretical discussion will use all orbitals of all contributing atoms. A first approximation might use a <a href="/wiki/Linear_combination_of_atomic_orbitals" title="Linear combination of atomic orbitals">LCAO</a> of the <a href="/wiki/Molecular_orbital" title="Molecular orbital">molecular orbitals</a> in the <a href="/wiki/Polygon" title="Polygon">polygon</a> forming the base of the pyramid and the orbitals on the <a href="/wiki/Apex_(geometry)#Axial_(or_apical)_and_equatorial_positions" title="Apex (geometry)">apical</a> atom, as the carbon atom at the top of the pyramid. This approximation will provide insight into the intrinsic stability of the structures. </p> <div class="mw-heading mw-heading3"><h3 id="Apical_carbon_atom">Apical carbon atom</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=3" title="Edit section: Apical carbon atom"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Apical_(chemistry)" class="mw-redirect" title="Apical (chemistry)">apical</a> carbon atom is connected to only one other <a href="/wiki/Substituent" title="Substituent">substituent</a>, so an sp-<a href="/wiki/Orbital_hybridization" class="mw-redirect" title="Orbital hybridization">hybridisation</a> is to be expected. The substituent will be oriented upward. Towards the basic polygon, three orbitals are available: </p> <ul><li>The second sp-orbital. This orbital is relatively low in energy due to the contribution of the s-orbital. With respect to the nodal planes in the remaining p-orbitals the symmetry of this orbital can be written as <b>S<sub>x</sub>S<sub>y</sub></b>,<sup id="cite_ref-SymAntiSym_2-0" class="reference"><a href="#cite_note-SymAntiSym-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> symmetric with respect to both planes. The orbital has a rather low energy, in terms of the <a href="/wiki/H%C3%BCckel_method" title="Hückel method">Hückel method</a> its value is not easy to estimate, although it will be lower than α, since the orbital will have considerable s-character.</li> <li>Two p-orbitals. These orbitals have a higher energy content then the sp-orbital. In terms of the Huckel method, the energy will be α. In symmetry terms, these orbitals are <a href="/wiki/Orthogonal" class="mw-redirect" title="Orthogonal">orthogonal</a>, described as <b>A<sub>x</sub>S<sub>y</sub></b> and <b>S<sub>x</sub>A<sub>y</sub></b><sup id="cite_ref-SymAntiSym_2-1" class="reference"><a href="#cite_note-SymAntiSym-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading3"><h3 id="Base_of_the_pyramid">Base of the pyramid</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=4" title="Edit section: Base of the pyramid"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table style="float:right;background-color:#E8E8E8;"> <tbody><tr> <td width="320px"><b>Figure 2:</b> Orbitals of the apical carbon atom (above) and the MOs of the base (below)<sup id="cite_ref-SymAntiSym_2-2" class="reference"><a href="#cite_note-SymAntiSym-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f6/Pyramidal_ion_4_sided.jpg/300px-Pyramidal_ion_4_sided.jpg" decoding="async" width="300" height="125" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f6/Pyramidal_ion_4_sided.jpg/450px-Pyramidal_ion_4_sided.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f6/Pyramidal_ion_4_sided.jpg/600px-Pyramidal_ion_4_sided.jpg 2x" data-file-width="952" data-file-height="396" /></a><figcaption></figcaption></figure> </td></tr> <tr> <td><b>Figure 3:</b> Interaction between the apical and basal orbitals. The "A" on top is apical carbon, "P" indicates the pyramidal structure, "B" is for the basal part of the pyramid. </td></tr> <tr> <td><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_Orbital_interaction.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Pyramidal_ion_4_sided_Orbital_interaction.jpg/300px-Pyramidal_ion_4_sided_Orbital_interaction.jpg" decoding="async" width="300" height="250" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Pyramidal_ion_4_sided_Orbital_interaction.jpg/450px-Pyramidal_ion_4_sided_Orbital_interaction.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/3/3d/Pyramidal_ion_4_sided_Orbital_interaction.jpg 2x" data-file-width="551" data-file-height="459" /></a><figcaption></figcaption></figure> </td></tr></tbody></table> <p>The approximation for the base of the pyramid is a closed ring of carbon atoms, all of them sp<sup>2</sup> hybridised. The exact results depend on the ring size; overall conclusions can be formulated as: </p> <ul><li>The lowest molecular orbital has, watched from the apex of the pyramid, no nodal planes. Symmetry will be <b>S<sub>x</sub>S<sub>y</sub></b>.<sup id="cite_ref-SymAntiSym_2-3" class="reference"><a href="#cite_note-SymAntiSym-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> In the Hückel method, its energy is <span class="nowrap">(α - 2β)</span></li> <li>The next level of energy is occupied by two degenerated orbitals. In symmetry terms, they are written as <b>S<sub>x</sub>A<sub>y</sub></b> and <b>A<sub>x</sub>S<sub>y</sub></b>.<sup id="cite_ref-SymAntiSym_2-4" class="reference"><a href="#cite_note-SymAntiSym-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> The energy depends on the size of the ring:</li></ul> <table> <tbody><tr> <th align="center width=">ring size</th> <th align="center width=">energy level </th></tr> <tr> <td align="center">3</td> <td align="center">(α + β) </td></tr> <tr> <td align="center">4</td> <td align="center">α </td></tr> <tr> <td align="center">5</td> <td align="center">(α - 0.618β) </td></tr> <tr> <td align="center">6</td> <td align="center">(α - β) </td></tr></tbody></table> <ul><li>Depending on the size of the base, there will be other MOs, but they are irrelevant to the present discussion.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Interaction_between_apex_and_base">Interaction between apex and base</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=5" title="Edit section: Interaction between apex and base"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To obtain bonding interactions between atoms or parts of molecules, two conditions should be met: </p> <ul><li>The orbitals to combine should have the same symmetry.</li> <li>A smaller difference in energy between the combining orbitals will produce a greater stabilizing effect.</li></ul> <p>The orbitals at the apical carbon and the basic polygon are able to combine with respect to their symmetries. The result will be a more stable configuration for the pyramids. In figure 2, the symmetry aspects are depicted. </p> <ul><li>The apical sp orbital combines with the lowest MO of the basic ring to a low bonding and a high anti-bonding orbital.</li> <li>The two apical p orbitals combine with the second lowest energy levels in the basic ring. Two bonding and two anti-bonding orbitals result. Figure 3 is a graphical representation of the results.</li></ul> <p>Filling the atomic and molecular orbitals in pyramidal structures of different base size leads to the next table. Only bonding orbitals are accounted for. </p> <table class="wikitable"> <caption>Table 1: Distribution of electrons in pyramidal molecular structures of the type (CH)<sub>n</sub>:CH </caption> <tbody><tr> <th rowspan="2"> </th> <th colspan="2">n=3<br />(trigonal) </th> <th colspan="2">n=4<br />(square) </th> <th colspan="2">n=5<br />(pentagonal) </th> <th colspan="2">n=6<br />(hexagonal) </th></tr> <tr> <th>orbitals </th> <th>charge </th> <th>orbitals </th> <th>charge </th> <th>orbitals </th> <th>charge </th> <th>orbitals </th> <th>charge </th></tr> <tr> <td>1s orbitals on carbon</td> <td align="center">4</td> <td align="center">−8</td> <td align="center">5</td> <td align="center">−10</td> <td align="center">6</td> <td align="center">−12</td> <td align="center">7</td> <td align="center">−14 </td></tr> <tr> <td>σ bond between hydrogen and the apical carbon</td> <td align="center">1</td> <td align="center">−2</td> <td align="center">1</td> <td align="center">−2</td> <td align="center">1</td> <td align="center">−2</td> <td align="center">1</td> <td align="center">−2 </td></tr> <tr> <td>σ bond between hydrogen and the basic carbon</td> <td align="center">3</td> <td align="center">–6</td> <td align="center">4</td> <td align="center">–8</td> <td align="center">5</td> <td align="center">10</td> <td align="center">6</td> <td align="center">–12 </td></tr> <tr> <td>σ bond in between basic carbons</td> <td align="center">3</td> <td align="center">–6</td> <td align="center">4</td> <td align="center">–8</td> <td align="center">5</td> <td align="center">–10</td> <td align="center">6</td> <td align="center">–12 </td></tr> <tr> <td>bonding MO between apical and lowest basic orbital</td> <td align="center">1</td> <td align="center">–2</td> <td align="center">1</td> <td align="center">–2</td> <td align="center">1</td> <td align="center">–2</td> <td align="center">1</td> <td align="center">–2 </td></tr> <tr> <td>bonding MO between apical and second-lowest basic orbitals</td> <td align="center">2</td> <td align="center">–4</td> <td align="center">2</td> <td align="center">–4</td> <td align="center">2</td> <td align="center">–4</td> <td align="center">2</td> <td align="center">–4 </td></tr> <tr> <td>total number of electrons</td> <td colspan="2" align="center">–28</td> <td colspan="2" align="center">–34</td> <td colspan="2" align="center">–40</td> <td colspan="2" align="center">–46 </td></tr> <tr> <td>total nuclear charge: (n+1)*(C+H)=(n+1)*(6+1)</td> <td colspan="2" align="center">+28</td> <td colspan="2" align="center">+35</td> <td colspan="2" align="center">+42</td> <td colspan="2" align="center">+49 </td></tr> <tr> <td>Net charge of structure</td> <td colspan="2" align="center">0</td> <td colspan="2" align="center">1+</td> <td colspan="2" align="center">2+</td> <td colspan="2" align="center">3+ </td></tr></tbody></table> <p>In the case of the three-sided pyramid, clearly no ion results; a known neutral species arises: <a href="/wiki/Tetrahedrane" title="Tetrahedrane">tetrahedrane</a>. To this molecule this way of description is an alternative <a href="/wiki/Computational_chemistry" title="Computational chemistry">quantum mechanical description</a>. </p><p>The other pyramidal structures will be charged in relation with their base size. </p> <div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=6" title="Edit section: Examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Monocation">Monocation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=7" title="Edit section: Monocation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dd><b>Figure 4:</b> A number of derivatives of tricyclo[2,1,0,0<sup>2,4</sup>]pentane (TCP) leading to the same pyramidal cation. The carbon atom carrying the <a href="/wiki/Leaving_group" title="Leaving group">leaving group</a> becomes basic, while carbon at the <i>anti</i> position becomes apical.<br />The group "R" is either <sup>1</sup>H or <sup>2</sup>H (<a href="/wiki/Deuterium" title="Deuterium">D</a>):</dd></dl> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:3HO-1,4-diMe-tricyclo(2,1,0,02,5)pentaan.jpg" class="mw-file-description" title="4a: 3-hydroxy-1,4-dimethyl-TCP"><img alt="4a: 3-hydroxy-1,4-dimethyl-TCP" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/27/3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/120px-3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg" decoding="async" width="120" height="81" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/27/3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/180px-3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/27/3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/240px-3HO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 2x" data-file-width="392" data-file-height="266" /></a></span></div> <div class="gallerytext"><b>4a:</b><br />3-hydroxy-1,4-dimethyl-TCP</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:3HO-1,5-diMe-tricyclo(2,1,0,02,5)pentaan.jpg" class="mw-file-description" title="4b: 3-hydroxy-1,5-dimethyl-TCP"><img alt="4b: 3-hydroxy-1,5-dimethyl-TCP" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5a/3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/120px-3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg" decoding="async" width="120" height="67" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5a/3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/180px-3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5a/3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/240px-3HO-1%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 2x" data-file-width="479" data-file-height="267" /></a></span></div> <div class="gallerytext"><b>4b:</b><br />3-hydroxy-1,5-dimethyl-TCP</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:3MeO-3,5-diMe-tricyclo(2,1,0,02,5)pentaan.jpg" class="mw-file-description" title="4c: 3-methoxy-3,5-dimethyl-TCP"><img alt="4c: 3-methoxy-3,5-dimethyl-TCP" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/120px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg" decoding="async" width="120" height="79" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/180px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/240px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 2x" data-file-width="447" data-file-height="294" /></a></span></div> <div class="gallerytext"><b>4c:</b><br />3-methoxy-3,5-dimethyl-TCP</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Four_sided_Pyramidal_1,5-DiMe-3-R.jpg" class="mw-file-description" title="4d: resulting carbocation"><img alt="4d: resulting carbocation" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/48/Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg/120px-Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg" decoding="async" width="120" height="68" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/48/Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg/180px-Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/48/Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg/240px-Four_sided_Pyramidal_1%2C5-DiMe-3-R.jpg 2x" data-file-width="420" data-file-height="238" /></a></span></div> <div class="gallerytext"><b>4d:</b><br />resulting carbocation</div> </li> </ul> <p>In 1972 Masamune describes the results of dissolving a number of precursors to <i>4d</i> (figure 4) at <span class="nowrap">- 70°C.</span> in <a href="/wiki/Superacid" title="Superacid">superacid</a> (a mixture of SO<sub>2</sub>ClF and FSO<sub>3</sub>H). Based on both the <sup>13</sup>C as well as the <sup>1</sup>H-NMR-spectrum the evidence is clear: in each case the same intermediary is formed. Also, when the super acidic medium is destroyed, with either <a href="/wiki/Methanol" title="Methanol">methanol</a> or <a href="/wiki/Benzoic_acid" title="Benzoic acid">benzoic acid</a>, the same product is formed. (see: <a href="#Reaction_with_methanol_and_benzoic_acid">Reaction...</a> <i>below</i>).<sup id="cite_ref-Masamune_72b_3-0" class="reference"><a href="#cite_note-Masamune_72b-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <table align="center"> <caption><b>Table 2: NMR-data of the 1,5-dimethyl-pyramidal ion (relative to <a href="/wiki/Tetramethylsilane" title="Tetramethylsilane">TMS</a> = 0)</b><sup id="cite_ref-Masamune_72c_4-0" class="reference"><a href="#cite_note-Masamune_72c-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </caption> <tbody><tr> <th width="200px">group/atom(<sup> <b>!</b> </sup>)</th> <th width="100px"><sup>13</sup>C</th> <th width="100px"><sup>1</sup>H</th> <th> </th></tr> <tr style="text-align:center;"> <td>1</td> <td>93.56</td> <td>-</td> <td rowspan="6"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_with_numbers.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/200px-Pyramidal_ion_4_sided_with_numbers.jpg" decoding="async" width="200" height="125" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/300px-Pyramidal_ion_4_sided_with_numbers.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/400px-Pyramidal_ion_4_sided_with_numbers.jpg 2x" data-file-width="401" data-file-height="250" /></a></span> </td></tr> <tr style="text-align:center;"> <td>2 / 4</td> <td>73.00</td> <td>4.62 </td></tr> <tr style="text-align:center;"> <td>3 (if R= <sup>1</sup>H)</td> <td>60.97</td> <td>4.68 </td></tr> <tr style="text-align:center;"> <td>5</td> <td>-23.04</td> <td>- </td></tr> <tr style="text-align:center;"> <td>Methyl at 1</td> <td>7.45</td> <td>2.15 </td></tr> <tr style="text-align:center;"> <td>Methyl at 5</td> <td>-1.03</td> <td>1.84 </td></tr> <tr style="text-align:center;"> <td colspan="4">(<sup> <b>!</b> </sup>)In this table carbon atoms are called, in <sup>1</sup>H-NMR the signal of the hydrogen carried by the called carbons are depicted </td></tr></tbody></table> <ul><li>Assignment in the hydrogen spectrum is partly on intensity (hydrogens at the basic ring) partly on the common experience hydrogen's at the outer side of a circular conjugated system have signals at higher ppm relative to TMS, while those positioned over the ring will have lower, even negative, signals relative to TMS.</li> <li>Assignment in <sup>13</sup>C-NMR follow the same considerations as for <sup>1</sup>H. Though in carbon NMR intensity is a bad guide to the number of atoms, in the basic ring the unsubstituted carbons are similar enough to use intensity as indication for their number. A powerful tool too is the multiplicity of the carbon signal due to coupling with the to carbon bonded hydrogens.</li> <li>Masamune himself does not state anything about the nature of the intermediate ion.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> Nevertheless, based on rules formulated by Olah,<sup id="cite_ref-Olah_78a_6-0" class="reference"><a href="#cite_note-Olah_78a-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> he is able to rule out localized cations (like 1-butyl) or delocalized ones (like allyl). For those ions signals around 200 ppm are expected.</li></ul> <div class="mw-heading mw-heading4"><h4 id="Reaction_with_methanol_and_benzoic_acid">Reaction with methanol and benzoic acid</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=8" title="Edit section: Reaction with methanol and benzoic acid"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dd><b>Figure 5:</b> De reaction products of the dimethyl pyramidal cation with methanol and benzoic acid.<br />The "R"-group is either<sup>1</sup>H or <sup>2</sup>H (<a href="/wiki/Deuterium" title="Deuterium">D</a>):</dd></dl> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_with_numbers.jpg" class="mw-file-description" title="5a = 4d Pyramidal cation"><img alt="5a = 4d Pyramidal cation" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/120px-Pyramidal_ion_4_sided_with_numbers.jpg" decoding="async" width="120" height="75" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/180px-Pyramidal_ion_4_sided_with_numbers.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/39/Pyramidal_ion_4_sided_with_numbers.jpg/240px-Pyramidal_ion_4_sided_with_numbers.jpg 2x" data-file-width="401" data-file-height="250" /></a></span></div> <div class="gallerytext"><b>5a</b> = 4d<br />Pyramidal cation</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:3BzO-1,4-diMe-tricyclo(2,1,0,02,5)pentaan.jpg" class="mw-file-description" title="5b Reaction product with benzoic acid in dipolar aprotic solvent"><img alt="5b Reaction product with benzoic acid in dipolar aprotic solvent" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7d/3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/120px-3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg" decoding="async" width="120" height="81" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7d/3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/180px-3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7d/3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/240px-3BzO-1%2C4-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 2x" data-file-width="392" data-file-height="266" /></a></span></div> <div class="gallerytext"><b>5b</b><br />Reaction product with benzoic acid<br />in dipolar aprotic solvent</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:3MeO-3,5-diMe-tricyclo(2,1,0,02,5)pentaan.jpg" class="mw-file-description" title="5c reaction product with methanol in methanol"><img alt="5c reaction product with methanol in methanol" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/120px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg" decoding="async" width="120" height="79" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/180px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg/240px-3MeO-3%2C5-diMe-tricyclo%282%2C1%2C0%2C02%2C5%29pentaan.jpg 2x" data-file-width="447" data-file-height="294" /></a></span></div> <div class="gallerytext"><b>5c</b><br />reaction product with methanol<br />in methanol</div> </li> </ul> <p>As described above, independent from its synthetic route, pyramidal ion <b>5a</b> reacts with methanol or benzoate giving rise to products governed by reagent and the reaction medium as is clear by the substitution patterns. In 1972 Masamune <sup id="cite_ref-Masamune_72b_3-1" class="reference"><a href="#cite_note-Masamune_72b-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Masamune_72c_4-1" class="reference"><a href="#cite_note-Masamune_72c-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> is unable to explain the different behavior of the intermediate. In terms of the HSAB-theory an explanation might be given. </p><p>In 1975 Masamune calculated<sup id="cite_ref-Masamune_75d_7-0" class="reference"><a href="#cite_note-Masamune_75d-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> in the non-substituted ion most of the charge at the hydrogen atoms. Replacing hydrogen for carbon, the central atom of the methyl group, a more <a href="/wiki/Electronegativity" title="Electronegativity">electronegative</a> substituent (2.5 versus 2.1 on the Pauling scale) will concentrate charge on the skeletal carbon. This charge concentration has several effects: </p> <ul><li>The reaction with benzoate is governed by π - π interactions. The degeneration in the basic MO-system will be lost because of the presence of a substituting methyl group. As the apical side is inaccessible, benzoate will approach from the bottom side of the pyramid. The interaction between the two π-systems, both disturbed at one point, will force a specific orientation. The orientation in which the interaction between positive charge generated by the methyl group on the pyramid and the charge adjacent to the carboxyl group will direct the system to a reaction of the carboxyl group with carbon 2 or 4 of the pyramid base. When reaction with benzoate takes place at carbon 2 bridges will form between the apical carbon and atoms 1 and 3. A bond too will form between <i>anti</i>-carbon 4 and the apex. Reaction at carbon 4 will have a same effect, although the resulting molecule has a mirror relation with respect to the molecule that results from reaction at position 2.</li> <li>The reaction with methanol is charge driven. In de basic system an identifiable center of positive charge is present at the carbon carrying the methyl group. Methanol with its <a href="/wiki/HSAB_theory" title="HSAB theory">hard base</a> in oxygen, will react at the center of positivity. The methoxy group appears at carbon 1, forcing bridges to form between carbon 2 and 4 to the apex, as well as between the now <i>anti</i>-carbon 3.</li></ul> <div class="mw-heading mw-heading4"><h4 id="Bishomomonocarbocation">Bishomomonocarbocation</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=9" title="Edit section: Bishomomonocarbocation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In chemistry, the prefix "homo-" denotes a <a href="/wiki/Homologous_series" title="Homologous series">homolog</a>, a likewise compound containing one, or as in this case two, extra CH<sub>2</sub>-groups. The common aspect of the bishomo ions is the possession of a <a href="/wiki/1,4-cyclohexadiene" class="mw-redirect" title="1,4-cyclohexadiene">1,4-cyclohexadiene</a> ring instead of a <a href="/wiki/Cyclobutadiene" title="Cyclobutadiene">cyclobutadiene</a> one. </p> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_Bishomo_bridged.jpg" class="mw-file-description" title="Bridges between the homo-atoms bishomo-carbocation"><img alt="Bridges between the homo-atoms bishomo-carbocation" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/89/Pyramidal_ion_4_sided_Bishomo_bridged.jpg/115px-Pyramidal_ion_4_sided_Bishomo_bridged.jpg" decoding="async" width="115" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/89/Pyramidal_ion_4_sided_Bishomo_bridged.jpg/172px-Pyramidal_ion_4_sided_Bishomo_bridged.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/89/Pyramidal_ion_4_sided_Bishomo_bridged.jpg/230px-Pyramidal_ion_4_sided_Bishomo_bridged.jpg 2x" data-file-width="296" data-file-height="309" /></a></span></div> <div class="gallerytext"> Bridges between the homo-atoms bishomo-carbocation </div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg" class="mw-file-description" title="The planes containing the sp2 hybrised atoms and those atoms connected to them"><img alt="The planes containing the sp2 hybrised atoms and those atoms connected to them" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/36/Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg/120px-Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg" decoding="async" width="120" height="71" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/36/Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg/180px-Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/36/Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg/240px-Pyramidal_ion_4_sided_Bishomo_Unbridged_with_planes.jpg 2x" data-file-width="333" data-file-height="196" /></a></span></div> <div class="gallerytext"> The planes containing the sp<sup>2</sup> hybrised atoms and those atoms connected to them</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg" class="mw-file-description" title="Unbridges bishomo-carbocation"><img alt="Unbridges bishomo-carbocation" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg/120px-Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg" decoding="async" width="120" height="97" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg/180px-Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/06/Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg/240px-Pyramidal_ion_4_sided_Bishomo_Unbridged.jpg 2x" data-file-width="296" data-file-height="240" /></a></span></div> <div class="gallerytext"> Unbridges bishomo-carbocation </div> </li> </ul> <p>The stability of this ion at first may seem strange, as enlargement of the ring in general will diminish the bonding overlap between the orbitals at the center of the pyramidal structure. Here the sp<sup>2</sup> hybridization, and consequently the planarity of the atoms of and those directly bonded to the sp<sup>2</sup> centers, forces the tops of the p-orbitals of the basal carbons towards each other, thus creating a solid base for the apical carbon to sit on. Stiffening the configuration by a bridge between the homo-atoms, converting the base of the pyramid, to a <a href="/wiki/Norbornadiene" title="Norbornadiene">norbornadiene</a>, creates an even more stable structure. </p> <div class="mw-heading mw-heading3"><h3 id="Dication">Dication</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=10" title="Edit section: Dication"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>According to the results presented in Table 1, a five-sided pyramidal carbocation will be divalent. This is confirmed by theoretical<sup id="cite_ref-Hogeveen_1974a_8-0" class="reference"><a href="#cite_note-Hogeveen_1974a-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> and practical work by Hogeveen.<sup id="cite_ref-Hogeveen_1974b_9-0" class="reference"><a href="#cite_note-Hogeveen_1974b-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Hogeveen_1973a_10-0" class="reference"><a href="#cite_note-Hogeveen_1973a-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> In contrast to the monocation, which is described with several patterns of substitution, the dication is mainly studied by its hexamethyl derivative. The synthesis starts at <a href="/wiki/Hexamethyl_Dewar_benzene" class="mw-redirect" title="Hexamethyl Dewar benzene">hexamethyl Dewar benzene</a> (compound <b>I</b> in table 4) reacting with <a href="/wiki/Chlorine" title="Chlorine">Cl<sub>2</sub></a> into 5,6-dichloro-1,2,3,4,5,6-hexamethylbicyclo[2.1.1]hex-2-ene (compound <b>II</b> in table 4). Dissolution of this compound in <a href="/wiki/Fluorosulfonic_acid" class="mw-redirect" title="Fluorosulfonic acid">fluorosulfonic acid</a> gives rise to the dication (structure <b>III</b> in table 4). </p> <table align="center" style="background-color:#FFFFFF;"> <caption><b>Table 4: Synthetic route to the divalent pyramidal cation</b> </caption> <tbody><tr> <td width="200px"><span typeof="mw:File"><a href="/wiki/File:Hexamethyldewarbenzene_perspective.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hexamethyldewarbenzene_perspective.svg/200px-Hexamethyldewarbenzene_perspective.svg.png" decoding="async" width="200" height="160" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hexamethyldewarbenzene_perspective.svg/300px-Hexamethyldewarbenzene_perspective.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hexamethyldewarbenzene_perspective.svg/400px-Hexamethyldewarbenzene_perspective.svg.png 2x" data-file-width="300" data-file-height="240" /></a></span> </td> <td width="200px"><span typeof="mw:File"><a href="/wiki/File:Hexamethyldewarbenzene_with_chlorine.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Hexamethyldewarbenzene_with_chlorine.jpg/200px-Hexamethyldewarbenzene_with_chlorine.jpg" decoding="async" width="200" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Hexamethyldewarbenzene_with_chlorine.jpg/300px-Hexamethyldewarbenzene_with_chlorine.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/72/Hexamethyldewarbenzene_with_chlorine.jpg/400px-Hexamethyldewarbenzene_with_chlorine.jpg 2x" data-file-width="1094" data-file-height="800" /></a></span> </td> <td width="200px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_dikation,_hexamethyl.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Pyramidal_dikation%2C_hexamethyl.jpg/200px-Pyramidal_dikation%2C_hexamethyl.jpg" decoding="async" width="200" height="161" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Pyramidal_dikation%2C_hexamethyl.jpg/300px-Pyramidal_dikation%2C_hexamethyl.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Pyramidal_dikation%2C_hexamethyl.jpg/400px-Pyramidal_dikation%2C_hexamethyl.jpg 2x" data-file-width="742" data-file-height="598" /></a></span> </td></tr> <tr valign="top" align="center"> <td><b>I:</b> Me<sub>6</sub>-Dewar benzene</td> <td><b>II:</b> Product of reaction of Me<sub>6</sub> Dewar benzene with chlorine</td> <td><b>III:</b> the pyramidal dication </td></tr></tbody></table> <p>The presence of a pyramidal ion in the solution of fluorosulfonic acid is evidenced by the <sup>1</sup>H- and <sup>13</sup>C-NMR-spectrum (Table 5). </p> <table align="center" style="background-color:#FFFFFF;"> <caption><b>Table 5: NMR data of the pyramidal dication.</b> </caption> <tbody><tr> <th width="123">Intensity</th> <th width="123"><sup>1</sup>H</th> <th width="123"><sup>13</sup>C<sub>Singulet</sub></th> <th width="123"><sup>13</sup>C<sub>Quartet</sub> </th></tr> <tr align="center"> <td>1</td> <td>1.96(s)</td> <td>22,5</td> <td>- 2.0 </td></tr> <tr align="center"> <td>5</td> <td>2,65(s)</td> <td>126,3</td> <td>10,6 </td></tr></tbody></table> <p>The assignment of the signals is based on their intensities and multiplicities. The assignment of the pyramidal structure is based on the observed simplicity of the spectra: five equal C-CH<sub>3</sub> groups combined with one outstanding C-CH<sub>3</sub> group. The only way to construct a molecular entity from this data is a five-sided pyramid. Rapid equilibriums between degenerated classical or non-classical carbocations are discarded as the position of the signals does not match the expected values for those kind of structures.<sup id="cite_ref-Hogeveen_1974a_8-1" class="reference"><a href="#cite_note-Hogeveen_1974a-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>The crystal structure of [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup> (SbF<sub>6</sub><sup>−</sup>)<sub>2</sub> • HSO<sub>3</sub>F was obtained in 2017. Although the apical carbon atom is hexacoordinated, the rule of the tetravalency of carbon is still fulfilled. While the C-CH<sub>3</sub> bond length of 1.479(3) Å is typical for a C-C single bond, the other five very long C-C distances of 1.694(2)-1.715(3) Å indicate a bond order of <1.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Reactions_of_the_dication">Reactions of the dication</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=11" title="Edit section: Reactions of the dication"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table align="right"> <tbody><tr> <th>Figure 6: Reactions of the pyramidal carbodikation </th></tr> <tr> <td><figure class="mw-halign-right" typeof="mw:File"><a href="/wiki/File:Pyramidal_dication_reactions.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Pyramidal_dication_reactions.jpg/500px-Pyramidal_dication_reactions.jpg" decoding="async" width="500" height="371" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Pyramidal_dication_reactions.jpg/750px-Pyramidal_dication_reactions.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Pyramidal_dication_reactions.jpg/1000px-Pyramidal_dication_reactions.jpg 2x" data-file-width="2544" data-file-height="1888" /></a><figcaption></figcaption></figure> </td></tr> <tr> <td> <ul><li>Thermal reaction (above)</li> <li>Reaction with charged nucleofiles (middle)</li> <li>Reaction with uncharged nucleofile (bottom)</li></ul> </td></tr></tbody></table> <p>The reactions of the dication fall apart into three groups:<sup id="cite_ref-Hogeveen_1974b_9-1" class="reference"><a href="#cite_note-Hogeveen_1974b-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Hogeveen_1973a_10-1" class="reference"><a href="#cite_note-Hogeveen_1973a-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p> <ul><li><b>Thermal reactions</b> The hexamethyl substituted dication is a stable structure up to 40 °C (104 °F). Above this temperature reaction occurs: a <a href="/wiki/Hydride" title="Hydride">hydride</a>-ion is taken up, followed by an irreversible rearrangement to an <a href="/wiki/Arenium_ion" title="Arenium ion">arenium ion</a> which is stable in the fluorosulfonic acid medium (see: Figure 6, upper reaction).</li> <li><b>Charged nucleophiles</b> (hydride, methoxide, hydroxide) react reversible, leading to, independent of the nucleofile at hand, identical 2,4-substituted tricyclo[3.1.0.0<sup>3,6</sup>]hexane derivatis, e.g.: with methoxide: 2,4-dimethoxy-tricyclo[3.1.0.0<sup>3,6</sup>]hexane is formed (see: Figure 6, middle reaction path).</li> <li>Uncharged nucleofiles (<a href="/wiki/Amine" title="Amine">amines</a> like <a href="/wiki/Triethylamine" title="Triethylamine">triethylamine</a>) act as a base, reversible extracting two hydrogens from the ion, in effect producing a dimethylene derivative of <a href="/wiki/Benzvalene" title="Benzvalene">benzvalene</a> (see: Figure 6, lower reaction).</li></ul> <div class="mw-heading mw-heading4"><h4 id="Other_substitution_patterns_at_the_dications">Other substitution patterns at the dications</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=12" title="Edit section: Other substitution patterns at the dications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The product of the reaction of the dication with <a href="/wiki/Triethylamine" title="Triethylamine">triethylamine</a> offers a pathway to other substitution patterns then hexamethyl.<sup id="cite_ref-Hogeveen_1977_12-0" class="reference"><a href="#cite_note-Hogeveen_1977-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> One or both double bonds are oxidized to a keton. The keton then is reacted with an <a href="/wiki/Organometallic_chemistry" title="Organometallic chemistry">organometallic compound</a> producing an alkylated hydroxide. The compounds formed in this way possess one or two other alkyl groups, depending on the number of oxidized double bonds. When the <a href="/wiki/Alcohol_(chemistry)" title="Alcohol (chemistry)">alcohols</a> are dissolved in <a href="/wiki/Fluorosulfonic_acid" class="mw-redirect" title="Fluorosulfonic acid">fluorosulfonic acid</a>, they again give rise to new pyramidal dications. Both non-methyl groups occupy basal positions. Each other position at the pyramidal skeleton still carries a methyl group. Table 6 summarizes these findings. </p> <table align="center" style="background-color:#FFFFFF;"> <caption><b>Table 6:</b> Synthesis of other pyramidal carbocations: R = <a href="/wiki/Ethyl_group" title="Ethyl group">ethyl</a> or <a href="/wiki/Isopropyl" class="mw-redirect" title="Isopropyl">isopropyl</a> </caption> <tbody><tr align="center"> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Dikation_Reaction_Product_with_Amine.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Pyramidal_Dikation_Reaction_Product_with_Amine.jpg/150px-Pyramidal_Dikation_Reaction_Product_with_Amine.jpg" decoding="async" width="150" height="137" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Pyramidal_Dikation_Reaction_Product_with_Amine.jpg/225px-Pyramidal_Dikation_Reaction_Product_with_Amine.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Pyramidal_Dikation_Reaction_Product_with_Amine.jpg/300px-Pyramidal_Dikation_Reaction_Product_with_Amine.jpg 2x" data-file-width="874" data-file-height="796" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/35/Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg/150px-Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg" decoding="async" width="150" height="136" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/35/Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg/225px-Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/35/Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg/300px-Pyramidal_Dikation_Reaction_Product_with_Amine_monoketon.jpg 2x" data-file-width="838" data-file-height="762" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg/150px-Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg" decoding="async" width="150" height="136" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg/225px-Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg/300px-Pyramidal_Dikation_Reaction_Product_with_Amine_mono_alcohol.jpg 2x" data-file-width="838" data-file-height="762" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Carbocation_X5Y_first_ionisation.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Pyramidal_Carbocation_X5Y_first_ionisation.jpg/150px-Pyramidal_Carbocation_X5Y_first_ionisation.jpg" decoding="async" width="150" height="115" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Pyramidal_Carbocation_X5Y_first_ionisation.jpg/225px-Pyramidal_Carbocation_X5Y_first_ionisation.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Pyramidal_Carbocation_X5Y_first_ionisation.jpg/300px-Pyramidal_Carbocation_X5Y_first_ionisation.jpg 2x" data-file-width="732" data-file-height="562" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Carbocation_X5Y_second_ionisation.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Pyramidal_Carbocation_X5Y_second_ionisation.jpg/150px-Pyramidal_Carbocation_X5Y_second_ionisation.jpg" decoding="async" width="150" height="124" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Pyramidal_Carbocation_X5Y_second_ionisation.jpg/225px-Pyramidal_Carbocation_X5Y_second_ionisation.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Pyramidal_Carbocation_X5Y_second_ionisation.jpg/300px-Pyramidal_Carbocation_X5Y_second_ionisation.jpg 2x" data-file-width="740" data-file-height="614" /></a></span> </td></tr> <tr align="center" valign="top"> <td><b>I:</b> Reactionproduct with Et<sub>3</sub>N</td> <td><b>II:</b> The monoketon</td> <td><b>III:</b> alkylated monoalcohol</td> <td><b>IV:</b> The pyramidal ion when dissolved the first time in FSO<sub>3</sub>H</td> <td><b>V:</b> The pyramidal cation when dissolved a second time in FSO<sub>3</sub>H </td></tr> <tr align="center"> <td> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg/150px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg" decoding="async" width="150" height="128" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg/225px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg/300px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diketon.jpg 2x" data-file-width="894" data-file-height="760" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/56/Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg/150px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg" decoding="async" width="150" height="124" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/56/Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg/225px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/56/Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg/300px-Pyramidal_Dikation_Reaction_Product_with_Amine_Diol.jpg 2x" data-file-width="924" data-file-height="762" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Carbocation_X4Y2_first_ionisation.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Pyramidal_Carbocation_X4Y2_first_ionisation.jpg/150px-Pyramidal_Carbocation_X4Y2_first_ionisation.jpg" decoding="async" width="150" height="112" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Pyramidal_Carbocation_X4Y2_first_ionisation.jpg/225px-Pyramidal_Carbocation_X4Y2_first_ionisation.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Pyramidal_Carbocation_X4Y2_first_ionisation.jpg/300px-Pyramidal_Carbocation_X4Y2_first_ionisation.jpg 2x" data-file-width="776" data-file-height="580" /></a></span> </td> <td width="150px"><span typeof="mw:File"><a href="/wiki/File:Pyramidal_Carbocation_X4Y2_second_ionisation.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/Pyramidal_Carbocation_X4Y2_second_ionisation.jpg/150px-Pyramidal_Carbocation_X4Y2_second_ionisation.jpg" decoding="async" width="150" height="124" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/66/Pyramidal_Carbocation_X4Y2_second_ionisation.jpg/225px-Pyramidal_Carbocation_X4Y2_second_ionisation.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/66/Pyramidal_Carbocation_X4Y2_second_ionisation.jpg/300px-Pyramidal_Carbocation_X4Y2_second_ionisation.jpg 2x" data-file-width="740" data-file-height="614" /></a></span> </td></tr> <tr align="center" valign="top"> <td></td> <td><b>II:</b> The diketon</td> <td><b>III:</b> alkylated diol</td> <td><b>IV:</b> The pyramidal ion when dissolved the first time in FSO<sub>3</sub>H</td> <td><b>V:</b> The pyramidal cation when dissolved a second time in FSO<sub>3</sub>H </td></tr></tbody></table> <p>Up to this point the substitution pattern of the divalent pyramidal ion is of minor importance to its behavior. A clear difference arises when the thermal stability if the ions of type <b>V</b> (Table 6) is studied: <span class="nowrap">at −40 °C (−40 °F)</span> the apical ethyl substituted ion is stable for 48 hours, whereas no trace of the apical <i>iso</i>-propyl ion is detectable anymore. </p> <div class="mw-heading mw-heading3"><h3 id="Tervalent_and_higher_ions">Tervalent and higher ions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=13" title="Edit section: Tervalent and higher ions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>At the time of the literature survey (end of 1978), there were no reports on tervalent or higher pyramidal cations. </p> <div class="mw-heading mw-heading2"><h2 id="Notes_and_references">Notes and references</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Pyramidal_carbocation&action=edit&section=14" title="Edit section: Notes and references"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Stohrer_72-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-Stohrer_72_1-0">^</a></b></span> <span class="reference-text"><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 id="CITEREFStohrerHoffmann1972" class="citation journal cs1">Stohrer, W.D.; Hoffmann, R. (1972). "Bond-stretch isomerism and polytopal rearrangements in (CH)5+, (CH)5-, and (CH)4CO". <i>J. Am. Chem. Soc</i>. <b>94</b> (5): 1661–1668. <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%2Fja00760a039">10.1021/ja00760a039</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=J.+Am.+Chem.+Soc.&rft.atitle=Bond-stretch+isomerism+and+polytopal+rearrangements+in+%28CH%295%2B%2C+%28CH%295-%2C+and+%28CH%294CO&rft.volume=94&rft.issue=5&rft.pages=1661-1668&rft.date=1972&rft_id=info%3Adoi%2F10.1021%2Fja00760a039&rft.aulast=Stohrer&rft.aufirst=W.D.&rft.au=Hoffmann%2C+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-SymAntiSym-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-SymAntiSym_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-SymAntiSym_2-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-SymAntiSym_2-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-SymAntiSym_2-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-SymAntiSym_2-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><b>S</b> indicating the orbital is symmetric with respect to the plane indicated by the subscript. An <b>A</b> describes an anti-symmetry with respect to the by the subscript indicated plane.</span> </li> <li id="cite_note-Masamune_72b-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-Masamune_72b_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Masamune_72b_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMasamuneSakaiOna1972" class="citation journal cs1">Masamune, S.; Sakai, M.; Ona, H. (1972). "Nature of the (CH)<sub>5</sub><sup>+</sup> species. I. Solvolysis of 1,5-dimethyltricyclo[2.1.0.0<sup>2,5</sup>]pent-3-yl benzoate". <i>J. Am. Chem. Soc</i>. <b>94</b> (25): 8955–8956. <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%2Fja00780a078">10.1021/ja00780a078</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=J.+Am.+Chem.+Soc.&rft.atitle=Nature+of+the+%28CH%29%3Csub%3E5%3C%2Fsub%3E%3Csup%3E%2B%3C%2Fsup%3E+species.+I.+Solvolysis+of+1%2C5-dimethyltricyclo%5B2.1.0.0%3Csup%3E2%2C5%3C%2Fsup%3E%5Dpent-3-yl+benzoate&rft.volume=94&rft.issue=25&rft.pages=8955-8956&rft.date=1972&rft_id=info%3Adoi%2F10.1021%2Fja00780a078&rft.aulast=Masamune&rft.aufirst=S.&rft.au=Sakai%2C+M.&rft.au=Ona%2C+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Masamune_72c-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-Masamune_72c_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Masamune_72c_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFS._MasamuneSakaiOnaJones1972" class="citation journal cs1">S. Masamune, S.; Sakai, M.; Ona, H.; Jones, A.J. (1972). "Nature of the (CH)<sub>5</sub><sup>+</sup> species. II. Direct observation of the carbonium ion of 3-hydroxyhomotetrahedrane derivatives". <i>J. Am. Chem. Soc</i>. <b>94</b> (25): 8956. <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%2Fja00780a079">10.1021/ja00780a079</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=J.+Am.+Chem.+Soc.&rft.atitle=Nature+of+the+%28CH%29%3Csub%3E5%3C%2Fsub%3E%3Csup%3E%2B%3C%2Fsup%3E+species.+II.+Direct+observation+of+the+carbonium+ion+of+3-hydroxyhomotetrahedrane+derivatives&rft.volume=94&rft.issue=25&rft.pages=8956&rft.date=1972&rft_id=info%3Adoi%2F10.1021%2Fja00780a079&rft.aulast=S.+Masamune&rft.aufirst=S.&rft.au=Sakai%2C+M.&rft.au=Ona%2C+H.&rft.au=Jones%2C+A.J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">Although Masamune presents his practical results later the same year as Stöhrer and Hoffmann their theoretical ones, it is unlikely Masamune was able to edit his paper at the moment the implications of the theoretical work became clear.</span> </li> <li id="cite_note-Olah_78a-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-Olah_78a_6-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOlahDonovanPrakash1978" class="citation journal cs1">Olah, G.A.; Donovan, D.J.; Prakash, G. (1978). "The α, 1-dimethylcyclopropylcarbinyl cation". <i>Tetrahedron Letters</i>. <b>19</b> (48): 4779–4782. <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%2Fs0040-4039%2801%2985729-4">10.1016/s0040-4039(01)85729-4</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Tetrahedron+Letters&rft.atitle=The+%CE%B1%2C+1-dimethylcyclopropylcarbinyl+cation&rft.volume=19&rft.issue=48&rft.pages=4779-4782&rft.date=1978&rft_id=info%3Adoi%2F10.1016%2Fs0040-4039%2801%2985729-4&rft.aulast=Olah&rft.aufirst=G.A.&rft.au=Donovan%2C+D.J.&rft.au=Prakash%2C+G.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Masamune_75d-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-Masamune_75d_7-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMasamune1975" class="citation journal cs1">Masamune, S. (1975). <a rel="nofollow" class="external text" href="https://doi.org/10.1351%2Fpac197544040861">"Some aspects of strained systems. [4]Annulene and its CH+ adduct"</a>. <i>Pure and Applied Chemistry</i>. <b>44</b> (4): 861–884. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1351%2Fpac197544040861">10.1351/pac197544040861</a></span>.</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=Some+aspects+of+strained+systems.+%5B4%5DAnnulene+and+its+CH%2B+adduct&rft.volume=44&rft.issue=4&rft.pages=861-884&rft.date=1975&rft_id=info%3Adoi%2F10.1351%2Fpac197544040861&rft.aulast=Masamune&rft.aufirst=S.&rft_id=https%3A%2F%2Fdoi.org%2F10.1351%252Fpac197544040861&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Hogeveen_1974a-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-Hogeveen_1974a_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Hogeveen_1974a_8-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHogeveenKwantPostmavan_Duynen1974" class="citation journal cs1">Hogeveen, H.; Kwant, P. W.; Postma, J.; van Duynen, P. Th. (1974). "Electronic spectra of pyramidal dications, (CCH<sub>3</sub>)<sub>6</sub><sup>2+</sup> and (CCH)<sub>6</sub><sup>2+</sup>". <i>Tetrahedron Letters</i>. <b>15</b> (49–50): 4351–4354. <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%2FS0040-4039%2801%2992161-6">10.1016/S0040-4039(01)92161-6</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Tetrahedron+Letters&rft.atitle=Electronic+spectra+of+pyramidal+dications%2C+%28CCH%3Csub%3E3%3C%2Fsub%3E%29%3Csub%3E6%3C%2Fsub%3E%3Csup%3E2%2B%3C%2Fsup%3E+and+%28CCH%29%3Csub%3E6%3C%2Fsub%3E%3Csup%3E2%2B%3C%2Fsup%3E&rft.volume=15&rft.issue=49%E2%80%9350&rft.pages=4351-4354&rft.date=1974&rft_id=info%3Adoi%2F10.1016%2FS0040-4039%2801%2992161-6&rft.aulast=Hogeveen&rft.aufirst=H.&rft.au=Kwant%2C+P.+W.&rft.au=Postma%2C+J.&rft.au=van+Duynen%2C+P.+Th.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Hogeveen_1974b-9"><span class="mw-cite-backlink">^ <a href="#cite_ref-Hogeveen_1974b_9-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Hogeveen_1974b_9-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHogeveenKwant1974" class="citation journal cs1">Hogeveen, H.; Kwant, P. W. (1974). "Chemistry and spectroscopy in strongly acidic solutions. XL. (CCH<sub>3</sub>)<sub>6</sub><sup>2+</sup>, an unusual dication". <i>Journal of the American Chemical Society</i>. <b>96</b> (7): 2208–2214. <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%2Fja00814a034">10.1021/ja00814a034</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=Chemistry+and+spectroscopy+in+strongly+acidic+solutions.+XL.+%28CCH%3Csub%3E3%3C%2Fsub%3E%29%3Csub%3E6%3C%2Fsub%3E%3Csup%3E2%2B%3C%2Fsup%3E%2C+an+unusual+dication&rft.volume=96&rft.issue=7&rft.pages=2208-2214&rft.date=1974&rft_id=info%3Adoi%2F10.1021%2Fja00814a034&rft.aulast=Hogeveen&rft.aufirst=H.&rft.au=Kwant%2C+P.+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Hogeveen_1973a-10"><span class="mw-cite-backlink">^ <a href="#cite_ref-Hogeveen_1973a_10-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Hogeveen_1973a_10-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHogeveenKwant1973" class="citation journal cs1">Hogeveen, H.; Kwant, P. W. (1973). "Direct observation of a remarkably stable dication of unusual structure: (CCH<sub>3</sub>)<sub>6</sub><sup>2⊕</sup>". <i>Tetrahedron Letters</i>. <b>14</b> (19): 1665–1670. <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%2FS0040-4039%2801%2996023-X">10.1016/S0040-4039(01)96023-X</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Tetrahedron+Letters&rft.atitle=Direct+observation+of+a+remarkably+stable+dication+of+unusual+structure%3A+%28CCH%3Csub%3E3%3C%2Fsub%3E%29%3Csub%3E6%3C%2Fsub%3E%3Csup%3E2%E2%8A%95%3C%2Fsup%3E&rft.volume=14&rft.issue=19&rft.pages=1665-1670&rft.date=1973&rft_id=info%3Adoi%2F10.1016%2FS0040-4039%2801%2996023-X&rft.aulast=Hogeveen&rft.aufirst=H.&rft.au=Kwant%2C+P.+W.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMalischewskiSeppelt2016" class="citation journal cs1">Malischewski, Moritz; Seppelt, K. (2016-11-25). "Crystal Structure Determination of the Pentagonal-Pyramidal Hexamethylbenzene Dication C6(CH3)6 2+". <i>Angewandte Chemie International Edition</i>. <b>56</b> (1): 368–370. <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%2Fanie.201608795">10.1002/anie.201608795</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/1433-7851">1433-7851</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/27885766">27885766</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+International+Edition&rft.atitle=Crystal+Structure+Determination+of+the+Pentagonal-Pyramidal+Hexamethylbenzene+Dication+C6%28CH3%296+2%2B&rft.volume=56&rft.issue=1&rft.pages=368-370&rft.date=2016-11-25&rft.issn=1433-7851&rft_id=info%3Apmid%2F27885766&rft_id=info%3Adoi%2F10.1002%2Fanie.201608795&rft.aulast=Malischewski&rft.aufirst=Moritz&rft.au=Seppelt%2C+K.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> <li id="cite_note-Hogeveen_1977-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-Hogeveen_1977_12-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFG._GiordanoHeldewegHogeveen1977" class="citation journal cs1">G. Giordano, G.; Heldeweg, R.; Hogeveen, H. (1977). "Pyramidal dications. Introduction of basal and apical substituents". <i>J. Am. Chem. Soc</i>. <b>99</b> (15): 5181–5183. <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%2Fja00457a050">10.1021/ja00457a050</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=J.+Am.+Chem.+Soc.&rft.atitle=Pyramidal+dications.+Introduction+of+basal+and+apical+substituents&rft.volume=99&rft.issue=15&rft.pages=5181-5183&rft.date=1977&rft_id=info%3Adoi%2F10.1021%2Fja00457a050&rft.aulast=G.+Giordano&rft.aufirst=G.&rft.au=Heldeweg%2C+R.&rft.au=Hogeveen%2C+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3APyramidal+carbocation" class="Z3988"></span></span> </li> </ol></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" 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=Pyramidal_carbocation&oldid=1256121341">https://en.wikipedia.org/w/index.php?title=Pyramidal_carbocation&oldid=1256121341</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:Cations" title="Category:Cations">Cations</a></li><li><a href="/wiki/Category:Reactive_intermediates" title="Category:Reactive intermediates">Reactive intermediates</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:Wikipedia_articles_that_are_too_technical_from_February_2017" title="Category:Wikipedia articles that are too technical from February 2017">Wikipedia articles that are too technical from February 2017</a></li><li><a href="/wiki/Category:All_articles_that_are_too_technical" title="Category:All articles that are too technical">All articles that are too technical</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 November 2024, at 09:20<span class="anonymous-show"> (UTC)</span>.</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=Pyramidal_carbocation&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" 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-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-6df7948d6c-ccpzx","wgBackendResponseTime":191,"wgPageParseReport":{"limitreport":{"cputime":"0.329","walltime":"0.519","ppvisitednodes":{"value":848,"limit":1000000},"postexpandincludesize":{"value":24199,"limit":2097152},"templateargumentsize":{"value":65,"limit":2097152},"expansiondepth":{"value":7,"limit":100},"expensivefunctioncount":{"value":2,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":52582,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 345.161 1 -total"," 42.26% 145.868 10 Template:Cite_journal"," 24.32% 83.933 1 Template:Technical"," 19.50% 67.321 1 Template:Ambox"," 9.01% 31.094 2 Template:Cvt"," 0.95% 3.296 3 Template:Nowrap"]},"scribunto":{"limitreport-timeusage":{"value":"0.170","limit":"10.000"},"limitreport-memusage":{"value":6824874,"limit":52428800}},"cachereport":{"origin":"mw-web.eqiad.main-6dd864dd59-zntjx","timestamp":"20241108092009","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Pyramidal carbocation","url":"https:\/\/en.wikipedia.org\/wiki\/Pyramidal_carbocation","sameAs":"http:\/\/www.wikidata.org\/entity\/Q23011489","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q23011489","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":"2016-03-07T10:58:57Z","dateModified":"2024-11-08T09:20:06Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/3\/39\/Pyramidal_ion_4_sided_with_numbers.jpg"}</script> </body> </html>