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class="vector-toc-link" href="#Titanium"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2.1</span> <span>Titanium</span> </div> </a> <ul id="toc-Titanium-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Zirconium" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Zirconium"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2.2</span> <span>Zirconium</span> </div> </a> <ul id="toc-Zirconium-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Hafnium" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Hafnium"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2.3</span> <span>Hafnium</span> </div> </a> <ul id="toc-Hafnium-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Rutherfordium" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Rutherfordium"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2.4</span> <span>Rutherfordium</span> </div> </a> <ul id="toc-Rutherfordium-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Production" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Production"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Production</span> </div> </a> <ul id="toc-Production-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Occurrence" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Occurrence"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Occurrence</span> </div> </a> <ul id="toc-Occurrence-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Applications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Applications"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Applications</span> </div> </a> <ul id="toc-Applications-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Biological_occurrences" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Biological_occurrences"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Biological occurrences</span> </div> </a> <ul id="toc-Biological_occurrences-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Precautions" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Precautions"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Precautions</span> </div> </a> <ul id="toc-Precautions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bibliography" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Bibliography"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Bibliography</span> </div> </a> <ul id="toc-Bibliography-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">Group 4 element</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 58 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-58" 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">58 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B9%D9%86%D8%A7%D8%B5%D8%B1_%D8%A7%D9%84%D9%85%D8%AC%D9%85%D9%88%D8%B9%D8%A9_%D8%A7%D9%84%D8%B1%D8%A7%D8%A8%D8%B9%D8%A9" title="عناصر المجموعة الرابعة – Arabic" lang="ar" hreflang="ar" data-title="عناصر المجموعة الرابعة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Grupo_4_d%27a_tabla_periodica" title="Grupo 4 d'a tabla periodica – Aragonese" lang="an" hreflang="an" data-title="Grupo 4 d'a tabla periodica" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Elementos_del_grupu_4" title="Elementos del grupu 4 – Asturian" lang="ast" hreflang="ast" data-title="Elementos del grupu 4" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/D%C3%B6vri_sistemin_4-c%C3%BC_qrupu" title="Dövri sistemin 4-cü qrupu – Azerbaijani" lang="az" hreflang="az" data-title="Dövri sistemin 4-cü qrupu" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-ban mw-list-item"><a href="https://ban.wikipedia.org/wiki/Datu_golongan_4" title="Datu golongan 4 – Balinese" lang="ban" hreflang="ban" data-title="Datu golongan 4" data-language-autonym="Basa Bali" data-language-local-name="Balinese" class="interlanguage-link-target"><span>Basa Bali</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%9A%E0%A6%A4%E0%A7%81%E0%A6%B0%E0%A7%8D%E0%A6%A5_%E0%A6%B6%E0%A7%8D%E0%A6%B0%E0%A7%87%E0%A6%A3%E0%A7%80%E0%A6%B0_%E0%A6%AE%E0%A7%8C%E0%A6%B2" title="চতুর্থ শ্রেণীর মৌল – Bangla" lang="bn" hreflang="bn" data-title="চতুর্থ শ্রেণীর মৌল" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%93%D1%80%D1%83%D0%BF%D0%B0_4_%D0%BD%D0%B0_%D0%BF%D0%B5%D1%80%D0%B8%D0%BE%D0%B4%D0%B8%D1%87%D0%BD%D0%B0%D1%82%D0%B0_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B0" title="Група 4 на периодичната система – Bulgarian" lang="bg" hreflang="bg" data-title="Група 4 на периодичната система" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/4._grupa_hemijskih_elemenata" title="4. grupa hemijskih elemenata – Bosnian" lang="bs" hreflang="bs" data-title="4. grupa hemijskih elemenata" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Grup_4_de_la_taula_peri%C3%B2dica" title="Grup 4 de la taula periòdica – Catalan" lang="ca" hreflang="ca" data-title="Grup 4 de la taula periòdica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/4._skupina" title="4. skupina – Czech" lang="cs" hreflang="cs" data-title="4. skupina" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Elfen_Gr%C5%B5p_4" title="Elfen Grŵp 4 – Welsh" lang="cy" hreflang="cy" data-title="Elfen Grŵp 4" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Gruppe_4" title="Gruppe 4 – Danish" lang="da" hreflang="da" data-title="Gruppe 4" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Titangruppe" title="Titangruppe – German" lang="de" hreflang="de" data-title="Titangruppe" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Elementos_del_grupo_4" title="Elementos del grupo 4 – Spanish" lang="es" hreflang="es" data-title="Elementos del grupo 4" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Elemento_de_grupo_4" title="Elemento de grupo 4 – Esperanto" lang="eo" hreflang="eo" data-title="Elemento de grupo 4" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/4._taldeko_elementu" title="4. taldeko elementu – Basque" lang="eu" hreflang="eu" data-title="4. taldeko elementu" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%DA%AF%D8%B1%D9%88%D9%87_%DB%B4_%D8%AC%D8%AF%D9%88%D9%84_%D8%AA%D9%86%D8%A7%D9%88%D8%A8%DB%8C" title="گروه ۴ جدول تناوبی – Persian" lang="fa" hreflang="fa" data-title="گروه ۴ جدول تناوبی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Groupe_4_du_tableau_p%C3%A9riodique" title="Groupe 4 du tableau périodique – French" lang="fr" hreflang="fr" data-title="Groupe 4 du tableau périodique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/D%C3%BAil_Ghr%C3%BApa_4" title="Dúil Ghrúpa 4 – Irish" lang="ga" hreflang="ga" data-title="Dúil Ghrúpa 4" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Elementos_do_grupo_4" title="Elementos do grupo 4 – Galician" lang="gl" hreflang="gl" data-title="Elementos do grupo 4" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/4%EC%A1%B1_%EC%9B%90%EC%86%8C" title="4족 원소 – Korean" lang="ko" hreflang="ko" data-title="4족 원소" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%B8%E0%A4%AE%E0%A5%82%E0%A4%B9_%E0%A5%AA_%E0%A4%A4%E0%A4%A4%E0%A5%8D%E0%A4%B5" title="समूह ४ तत्व – Hindi" lang="hi" hreflang="hi" data-title="समूह ४ तत्व" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Unsur_golongan_4" title="Unsur golongan 4 – Indonesian" lang="id" hreflang="id" data-title="Unsur golongan 4" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Elementi_del_gruppo_4" title="Elementi del gruppo 4 – Italian" lang="it" hreflang="it" data-title="Elementi del gruppo 4" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A7%D7%91%D7%95%D7%A6%D7%AA_%D7%99%D7%A1%D7%95%D7%93%D7%95%D7%AA_4" title="קבוצת יסודות 4 – Hebrew" lang="he" hreflang="he" data-title="קבוצת יסודות 4" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Periodin%C4%97s_chemini%C5%B3_element%C5%B3_sistemos_IVB_grup%C4%97" title="Periodinės cheminių elementų sistemos IVB grupė – Lithuanian" lang="lt" hreflang="lt" data-title="Periodinės cheminių elementų sistemos IVB grupė" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Grupp_4_de_la_taula_peri%C3%B2dica" title="Grupp 4 de la taula periòdica – Lombard" lang="lmo" hreflang="lmo" data-title="Grupp 4 de la taula periòdica" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%93%D1%80%D1%83%D0%BF%D0%B0_4_%D0%BD%D0%B0_%D0%BF%D0%B5%D1%80%D0%B8%D0%BE%D0%B4%D0%BD%D0%B8%D0%BE%D1%82_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC" title="Група 4 на периодниот систем – Macedonian" lang="mk" hreflang="mk" data-title="Група 4 на периодниот систем" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Unsur_kumpulan_4" title="Unsur kumpulan 4 – Malay" lang="ms" hreflang="ms" data-title="Unsur kumpulan 4" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Titaangroep" title="Titaangroep – Dutch" lang="nl" hreflang="nl" data-title="Titaangroep" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E7%AC%AC4%E6%97%8F%E5%85%83%E7%B4%A0" title="第4族元素 – Japanese" lang="ja" hreflang="ja" data-title="第4族元素" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-frr mw-list-item"><a href="https://frr.wikipedia.org/wiki/Titaansk%C3%B6%C3%B6l" title="Titaanskööl – Northern Frisian" lang="frr" hreflang="frr" data-title="Titaanskööl" data-language-autonym="Nordfriisk" data-language-local-name="Northern Frisian" class="interlanguage-link-target"><span>Nordfriisk</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Gruppe_4" title="Gruppe 4 – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Gruppe 4" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Grop_4_de_la_taula_periodica" title="Grop 4 de la taula periodica – Occitan" lang="oc" hreflang="oc" data-title="Grop 4 de la taula periodica" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%97%E0%A8%B0%E0%A9%81%E0%A9%B1%E0%A8%AA_4_%E0%A8%A4%E0%A9%B1%E0%A8%A4" title="ਗਰੁੱਪ 4 ਤੱਤ – Punjabi" lang="pa" hreflang="pa" data-title="ਗਰੁੱਪ 4 ਤੱਤ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Tytanowce" title="Tytanowce – Polish" lang="pl" hreflang="pl" data-title="Tytanowce" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Elementos_do_Grupo_4" title="Elementos do Grupo 4 – Portuguese" lang="pt" hreflang="pt" data-title="Elementos do Grupo 4" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Grupa_Titanului" title="Grupa Titanului – Romanian" lang="ro" hreflang="ro" data-title="Grupa Titanului" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9F%D0%BE%D0%B4%D0%B3%D1%80%D1%83%D0%BF%D0%BF%D0%B0_%D1%82%D0%B8%D1%82%D0%B0%D0%BD%D0%B0" title="Подгруппа титана – Russian" lang="ru" hreflang="ru" data-title="Подгруппа титана" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Grupi_i_kat%C3%ABrt_i_elementeve_kimike" title="Grupi i katërt i elementeve kimike – Albanian" lang="sq" hreflang="sq" data-title="Grupi i katërt i elementeve kimike" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/4%E0%B7%80%E0%B6%B1_%E0%B6%9A%E0%B7%8F%E0%B6%AB%E0%B7%8A%E0%B6%A9%E0%B6%BA%E0%B7%9A_%E0%B6%B8%E0%B7%96%E0%B6%BD_%E0%B6%AF%E0%B7%8A%E2%80%8D%E0%B6%BB%E0%B7%80%E0%B7%8A%E2%80%8D%E0%B6%BA" title="4වන කාණ්ඩයේ මූල ද්‍රව්‍ය – Sinhala" lang="si" hreflang="si" data-title="4වන කාණ්ඩයේ මූල ද්‍රව්‍ය" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Group_4_element" title="Group 4 element – Simple English" lang="en-simple" hreflang="en-simple" data-title="Group 4 element" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/4._skupina" title="4. skupina – Slovak" lang="sk" hreflang="sk" data-title="4. skupina" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Titanova_skupina" title="Titanova skupina – Slovenian" lang="sl" hreflang="sl" data-title="Titanova skupina" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/Guruubka_4" title="Guruubka 4 – Somali" lang="so" hreflang="so" data-title="Guruubka 4" data-language-autonym="Soomaaliga" data-language-local-name="Somali" class="interlanguage-link-target"><span>Soomaaliga</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/4._%D0%B3%D1%80%D1%83%D0%BF%D0%B0_%D1%85%D0%B5%D0%BC%D0%B8%D1%98%D1%81%D0%BA%D0%B8%D1%85_%D0%B5%D0%BB%D0%B5%D0%BC%D0%B5%D0%BD%D0%B0%D1%82%D0%B0" title="4. група хемијских елемената – Serbian" lang="sr" hreflang="sr" data-title="4. група хемијских елемената" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/4._grupa_hemijskih_elemenata" title="4. grupa hemijskih elemenata – Serbo-Croatian" lang="sh" hreflang="sh" data-title="4. grupa hemijskih elemenata" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Ryhm%C3%A4n_4_alkuaine" title="Ryhmän 4 alkuaine – Finnish" lang="fi" hreflang="fi" data-title="Ryhmän 4 alkuaine" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Grupp_4-element" title="Grupp 4-element – Swedish" lang="sv" hreflang="sv" data-title="Grupp 4-element" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%A8%E0%AF%86%E0%AE%9F%E0%AF%81%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AF%81%E0%AE%B4%E0%AF%81_4_%E0%AE%A4%E0%AE%A9%E0%AE%BF%E0%AE%AE%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AE%B3%E0%AF%8D" title="நெடுங்குழு 4 தனிமங்கள் – Tamil" lang="ta" hreflang="ta" data-title="நெடுங்குழு 4 தனிமங்கள்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%97%E0%B1%8D%E0%B0%B0%E0%B1%82%E0%B0%AA%E0%B1%8D_4_%E0%B0%AE%E0%B1%82%E0%B0%B2%E0%B0%95%E0%B0%82" title="గ్రూప్ 4 మూలకం – Telugu" lang="te" hreflang="te" data-title="గ్రూప్ 4 మూలకం" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%98%E0%B8%B2%E0%B8%95%E0%B8%B8%E0%B8%AB%E0%B8%A1%E0%B8%B9%E0%B9%88_4" title="ธาตุหมู่ 4 – Thai" lang="th" hreflang="th" data-title="ธาตุหมู่ 4" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/4._grup_elementi" title="4. grup elementi – Turkish" lang="tr" hreflang="tr" data-title="4. grup elementi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%93%D1%80%D1%83%D0%BF%D0%B0_4_%D0%BF%D0%B5%D1%80%D1%96%D0%BE%D0%B4%D0%B8%D1%87%D0%BD%D0%BE%D1%97_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B8_%D0%B5%D0%BB%D0%B5%D0%BC%D0%B5%D0%BD%D1%82%D1%96%D0%B2" title="Група 4 періодичної системи елементів – Ukrainian" lang="uk" hreflang="uk" data-title="Група 4 періодичної системи елементів" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Nh%C3%B3m_nguy%C3%AAn_t%E1%BB%91_4" title="Nhóm nguyên tố 4 – Vietnamese" lang="vi" hreflang="vi" data-title="Nhóm nguyên tố 4" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/4%E6%97%8F%E5%85%83%E7%B4%A0" title="4族元素 – Wu" lang="wuu" hreflang="wuu" data-title="4族元素" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/4%E6%97%8F%E5%85%83%E7%B4%A0" title="4族元素 – Cantonese" lang="yue" hreflang="yue" data-title="4族元素" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/4%E6%97%8F%E5%85%83%E7%B4%A0" title="4族元素 – Chinese" lang="zh" hreflang="zh" data-title="4族元素" data-language-autonym="中文" data-language-local-name="Chinese" 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Click here for more information."><img alt="This is a good article. Click here for more information." src="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/19px-Symbol_support_vote.svg.png" decoding="async" width="19" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/29px-Symbol_support_vote.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/39px-Symbol_support_vote.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span></div></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Group of chemical elements</div> <table class="infobox" style="text-align:center; border:1px solid #a9a9a9; background:#f8f8f8; padding:2px; width:1em;"> <tbody><tr> <th colspan="2" style="text-align:center; background:#d8d8d8;">Group 4 <span class="nowrap">in the periodic table</span> </th></tr> <tr> <td colspan="2" style="text-align:center; width:1em; margin-top:1px; background:transparent; border:1px solid #a9a9a9;"><div style="background-color:transparent; color:inherit; margin:0; padding:0; text-align:center; border:none;"> <table style="empty-cells:hidden; border:none; padding:0; border-spacing:1px; border-collapse:separate; margin:0;"> <tbody><tr> <td style="border:none;padding:0;"><a href="/wiki/Hydrogen" title="Hydrogen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Hydrogen</span></a> </td> <td colspan="30" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Helium" title="Helium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Helium</span></a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Lithium" title="Lithium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Lithium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Beryllium" title="Beryllium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Beryllium</span></a> </td> <td colspan="24" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Boron" title="Boron"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Boron</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Carbon" title="Carbon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Carbon</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nitrogen" title="Nitrogen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Nitrogen</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Oxygen" title="Oxygen"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Oxygen</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Fluorine" title="Fluorine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Fluorine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neon" title="Neon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Neon</span></a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Sodium" title="Sodium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Sodium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Magnesium" title="Magnesium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Magnesium</span></a> </td> <td colspan="24" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Aluminium" title="Aluminium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Aluminium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Silicon" title="Silicon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Silicon</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Phosphorus" title="Phosphorus"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Phosphorus</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Sulfur" title="Sulfur"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Sulfur</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Chlorine" title="Chlorine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Chlorine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Argon" title="Argon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Argon</span></a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Potassium" title="Potassium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Potassium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Calcium" title="Calcium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Calcium</span></a> </td> <td colspan="14" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Scandium" title="Scandium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Scandium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Titanium" title="Titanium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff; border:1px solid black; box-sizing: border-box;;">Titanium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Vanadium" title="Vanadium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Vanadium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Chromium" title="Chromium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Chromium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Manganese" title="Manganese"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Manganese</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iron" title="Iron"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Iron</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cobalt" title="Cobalt"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Cobalt</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nickel" title="Nickel"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Nickel</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Copper" title="Copper"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Copper</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Zinc" title="Zinc"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Zinc</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gallium" title="Gallium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Gallium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Germanium" title="Germanium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Germanium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Arsenic" title="Arsenic"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Arsenic</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Selenium" title="Selenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Selenium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bromine" title="Bromine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Bromine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Krypton" title="Krypton"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Krypton</span></a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Rubidium" title="Rubidium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Rubidium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Strontium" title="Strontium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Strontium</span></a> </td> <td style="border:none;padding:0;; width:0;"> </td> <td colspan="13" style="border:none;padding:0;"> </td> <td style="border:none;padding:0;"><a href="/wiki/Yttrium" title="Yttrium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Yttrium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Zirconium" title="Zirconium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff; border:1px solid black; box-sizing: border-box;;">Zirconium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Niobium" title="Niobium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Niobium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Molybdenum" title="Molybdenum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Molybdenum</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Technetium" title="Technetium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Technetium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Ruthenium" title="Ruthenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Ruthenium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rhodium" title="Rhodium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Rhodium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Palladium" title="Palladium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Palladium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Silver" title="Silver"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Silver</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cadmium" title="Cadmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Cadmium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Indium" title="Indium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Indium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tin" title="Tin"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tin</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Antimony" title="Antimony"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Antimony</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tellurium" title="Tellurium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tellurium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iodine" title="Iodine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Iodine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Xenon" title="Xenon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Xenon</span></a> </td></tr> <tr style="border:none;padding:0;"> <td style="border:none;padding:0;"><a href="/wiki/Caesium" title="Caesium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Caesium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Barium" title="Barium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Barium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lanthanum" title="Lanthanum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Lanthanum</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Cerium" title="Cerium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Cerium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Praseodymium" title="Praseodymium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Praseodymium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neodymium" title="Neodymium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Neodymium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Promethium" title="Promethium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Promethium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Samarium" title="Samarium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Samarium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Europium" title="Europium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Europium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gadolinium" title="Gadolinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Gadolinium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Terbium" title="Terbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Terbium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Dysprosium" title="Dysprosium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Dysprosium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Holmium" title="Holmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Holmium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Erbium" title="Erbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Erbium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thulium" title="Thulium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Thulium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Ytterbium" title="Ytterbium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Ytterbium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lutetium" title="Lutetium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Lutetium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Hafnium" title="Hafnium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff; border:1px solid black; box-sizing: border-box;;">Hafnium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tantalum" title="Tantalum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Tantalum</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tungsten" title="Tungsten"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Tungsten</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rhenium" title="Rhenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Rhenium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Osmium" title="Osmium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Osmium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Iridium" title="Iridium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Iridium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Platinum" title="Platinum"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Platinum</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Gold" title="Gold"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Gold</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Mercury_(element)" title="Mercury (element)"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Mercury (element)</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thallium" title="Thallium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Thallium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lead" title="Lead"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Lead</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bismuth" title="Bismuth"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Bismuth</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Polonium" title="Polonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Polonium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Astatine" title="Astatine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Astatine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Radon" title="Radon"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Radon</span></a> </td></tr> <tr> <td style="border:none;padding:0;"><a href="/wiki/Francium" title="Francium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Francium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Radium" title="Radium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#ff9999;">Radium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Actinium" title="Actinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Actinium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Thorium" title="Thorium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Thorium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Protactinium" title="Protactinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Protactinium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Uranium" title="Uranium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Uranium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Neptunium" title="Neptunium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Neptunium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Plutonium" title="Plutonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Plutonium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Americium" title="Americium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Americium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Curium" title="Curium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Curium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Berkelium" title="Berkelium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Berkelium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Californium" title="Californium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Californium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Einsteinium" title="Einsteinium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Einsteinium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Fermium" title="Fermium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Fermium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Mendelevium" title="Mendelevium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Mendelevium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nobelium" title="Nobelium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#9bff99;">Nobelium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Lawrencium" title="Lawrencium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Lawrencium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Rutherfordium" title="Rutherfordium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff; border:1px solid black; box-sizing: border-box;;">Rutherfordium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Dubnium" title="Dubnium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Dubnium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Seaborgium" title="Seaborgium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Seaborgium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Bohrium" title="Bohrium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Bohrium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Hassium" title="Hassium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Hassium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Meitnerium" title="Meitnerium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Meitnerium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Darmstadtium" title="Darmstadtium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Darmstadtium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Roentgenium" title="Roentgenium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Roentgenium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Copernicium" title="Copernicium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#99ccff;">Copernicium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Nihonium" title="Nihonium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Nihonium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Flerovium" title="Flerovium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Flerovium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Moscovium" title="Moscovium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Moscovium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Livermorium" title="Livermorium"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Livermorium</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Tennessine" title="Tennessine"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Tennessine</span></a> </td> <td style="border:none;padding:0;"><a href="/wiki/Oganesson" title="Oganesson"><span style="display:block;width:6px;height:8px;overflow:hidden;padding:0;color:transparent;background-color:#fdff8c;">Oganesson</span></a> </td></tr></tbody></table> </div><div class="nowrap" style="font-size:88%; text-align:center;"><a href="/wiki/Group_3_element" title="Group 3 element">group 3</a> ← <span style="width:8px; border:1px solid black" title="">  </span> → <a href="/wiki/Group_5_element" title="Group 5 element">group 5</a></div> </td></tr> <tr> <td colspan="2"> <table border="0" cellpadding="0" style="text-align:left; margin=0;"> <tbody><tr> <th><a href="/wiki/Group_(periodic_table)" title="Group (periodic table)">IUPAC group number</a></th> <th>4 </th></tr> <tr> <td>Name by element</td> <td><span class="nowrap">titanium group</span> </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/Group_(periodic_table)#CAS_and_old_IUPAC" title="Group (periodic table)">CAS group number</a><br /><small>(US, pattern A-B-A)</small></div></td> <td>IVB </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/Group_(periodic_table)#CAS_and_old_IUPAC" title="Group (periodic table)">old IUPAC number</a><br /><small>(Europe, pattern A-B)</small></div></td> <td>IVA </td></tr></tbody></table> <hr /> </td></tr> <tr> <th colspan="2" style="text-align:left;">↓ <small><a href="/wiki/Period_(periodic_table)" title="Period (periodic table)">Period</a></small> </th></tr> <tr> <th><a href="/wiki/Period_4_element" title="Period 4 element">4</a> </th> <td title="Ti, Titanium" style="text-align:center; vertical-align:bottom; width:210px; background:#f0f0f0; border:2px solid #6e6e8e; ;"><div><span typeof="mw:File"><a href="/wiki/File:Titan-crystal_bar.JPG" class="mw-file-description" title="Titanium crystal bar"><img alt="Image: Titanium crystal bar" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/db/Titan-crystal_bar.JPG/210px-Titan-crystal_bar.JPG" decoding="async" width="210" height="132" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/db/Titan-crystal_bar.JPG/315px-Titan-crystal_bar.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/db/Titan-crystal_bar.JPG/420px-Titan-crystal_bar.JPG 2x" data-file-width="5572" data-file-height="3500" /></a></span></div><a href="/wiki/Titanium" title="Titanium">Titanium</a> (Ti)<br /><span style="color:#000000;">22</span> <small><a href="/wiki/Transition_metal" title="Transition metal">Transition metal</a></small> </td></tr> <tr> <th><a href="/wiki/Period_5_element" title="Period 5 element">5</a> </th> <td title="Zr, Zirconium" style="text-align:center; vertical-align:bottom; width:210px; background:#f0f0f0; border:2px solid #6e6e8e; ;"><div><span typeof="mw:File"><a href="/wiki/File:Zirconium_crystal_bar_and_1cm3_cube.jpg" class="mw-file-description" title="Zirconium crystal bar"><img alt="Image: Zirconium crystal bar" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Zirconium_crystal_bar_and_1cm3_cube.jpg/210px-Zirconium_crystal_bar_and_1cm3_cube.jpg" decoding="async" width="210" height="154" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Zirconium_crystal_bar_and_1cm3_cube.jpg/315px-Zirconium_crystal_bar_and_1cm3_cube.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/92/Zirconium_crystal_bar_and_1cm3_cube.jpg/420px-Zirconium_crystal_bar_and_1cm3_cube.jpg 2x" data-file-width="4758" data-file-height="3498" /></a></span></div><a href="/wiki/Zirconium" title="Zirconium">Zirconium</a> (Zr)<br /><span style="color:#000000;">40</span> <small><a href="/wiki/Transition_metal" title="Transition metal">Transition metal</a></small> </td></tr> <tr> <th><a href="/wiki/Period_6_element" title="Period 6 element">6</a> </th> <td title="Hf, Hafnium" style="text-align:center; vertical-align:bottom; width:210px; background:#f0f0f0; border:2px solid #6e6e8e; ;"><div><span typeof="mw:File"><a href="/wiki/File:Hf-crystal_bar.jpg" class="mw-file-description" title="Hafnium crystal bar"><img alt="Image: Hafnium crystal bar" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hf-crystal_bar.jpg/210px-Hf-crystal_bar.jpg" decoding="async" width="210" height="60" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hf-crystal_bar.jpg/315px-Hf-crystal_bar.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/38/Hf-crystal_bar.jpg/420px-Hf-crystal_bar.jpg 2x" data-file-width="5428" data-file-height="1544" /></a></span></div><a href="/wiki/Hafnium" title="Hafnium">Hafnium</a> (Hf)<br /><span style="color:#000000;">72</span> <small><a href="/wiki/Transition_metal" title="Transition metal">Transition metal</a></small> </td></tr> <tr> <th><a href="/wiki/Period_7_element" title="Period 7 element">7</a> </th> <td title="Rf, Rutherfordium" style="text-align:center; vertical-align:bottom; width:210px; background:#f0f0f0; border:2px dotted #6e6e8e; ;"><a href="/wiki/Rutherfordium" title="Rutherfordium">Rutherfordium</a> (Rf)<br /><span style="color:#000000;">104</span> <small><a href="/wiki/Transition_metal" title="Transition metal">Transition metal</a></small> </td></tr> <tr> <td colspan="2"> <hr /> <i>Legend</i><div class="center"> <div style="border:2px solid #6e6e8e; background:#f0f0f0; padding:0 2px;"><a href="/wiki/Primordial_element" class="mw-redirect" title="Primordial element">primordial element</a></div> <div style="border:2px dotted #6e6e8e; background:#f0f0f0; padding:0 2px;"><a href="/wiki/Synthetic_element" title="Synthetic element">synthetic element</a></div> </div> </td></tr></tbody></table> <p><b>Group 4</b> is the second group of <a href="/wiki/Transition_metal" title="Transition metal">transition metals</a> in the periodic table. It contains the four elements <a href="/wiki/Titanium" title="Titanium">titanium</a> (Ti), <a href="/wiki/Zirconium" title="Zirconium">zirconium</a> (Zr), <a href="/wiki/Hafnium" title="Hafnium">hafnium</a> (Hf), and <a href="/wiki/Rutherfordium" title="Rutherfordium">rutherfordium</a> (Rf). The group is also called the <b>titanium group</b> or <b>titanium family</b> after its lightest member. </p><p>As is typical for early transition metals, zirconium and hafnium have only the group <a href="/wiki/Oxidation_state" title="Oxidation state">oxidation state</a> of +4 as a major one, and are quite electropositive and have a less rich coordination chemistry. Due to the effects of the <a href="/wiki/Lanthanide_contraction" title="Lanthanide contraction">lanthanide contraction</a>, they are very similar in properties. Titanium is somewhat distinct due to its smaller size: it has a well-defined +3 state as well (although +4 is more stable). </p><p>All the group 4 elements are hard, <a href="/wiki/Refractory_metal" class="mw-redirect" title="Refractory metal">refractory metals</a>. Their inherent reactivity is completely masked due to the formation of a dense oxide layer that protects them from corrosion, as well as attack by many acids and alkalis. The first three of them occur naturally. Rutherfordium is strongly <a href="/wiki/Radioactive" class="mw-redirect" title="Radioactive">radioactive</a>: it does not occur naturally and must be produced by artificial synthesis, but its observed and theoretically predicted properties are consistent with it being a heavier homologue of hafnium. None of them have any biological role. </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=Group_4_element&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Zircon" title="Zircon">Zircon</a> was known as a gemstone from ancient times,<sup id="cite_ref-CRC2008_1-0" class="reference"><a href="#cite_note-CRC2008-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> but it was not known to contain a new element until the work of German chemist <a href="/wiki/Martin_Heinrich_Klaproth" title="Martin Heinrich Klaproth">Martin Heinrich Klaproth</a> in 1789. He analysed the zircon-containing mineral <a href="/wiki/Jargoon" title="Jargoon">jargoon</a> and found a new earth (oxide), but was unable to isolate the element from its oxide. Cornish chemist <a href="/wiki/Humphry_Davy" title="Humphry Davy">Humphry Davy</a> also attempted to isolate this new element in 1808 through <a href="/wiki/Electrolysis" title="Electrolysis">electrolysis</a>, but failed: he gave it the name zirconium.<sup id="cite_ref-nbb_2-0" class="reference"><a href="#cite_note-nbb-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> In 1824, Swedish chemist <a href="/wiki/J%C3%B6ns_Jakob_Berzelius" class="mw-redirect" title="Jöns Jakob Berzelius">Jöns Jakob Berzelius</a> isolated an impure form of zirconium, obtained by heating a mixture of potassium and potassium zirconium fluoride in an iron tube.<sup id="cite_ref-CRC2008_1-1" class="reference"><a href="#cite_note-CRC2008-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>Cornish mineralogist <a href="/wiki/William_Gregor" title="William Gregor">William Gregor</a> first identified titanium in ilmenite sand beside a stream in <a href="/wiki/Cornwall" title="Cornwall">Cornwall</a>, Great Britain in the year 1791.<sup id="cite_ref-Emsley2001p452_3-0" class="reference"><a href="#cite_note-Emsley2001p452-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> After analyzing the sand, he determined the weakly magnetic sand to contain <a href="/wiki/Iron_oxide" title="Iron oxide">iron oxide</a> and a metal oxide that he could not identify.<sup id="cite_ref-Barksdale1968p732_4-0" class="reference"><a href="#cite_note-Barksdale1968p732-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> During that same year, mineralogist <a href="/wiki/Franz_Joseph_Muller" class="mw-redirect" title="Franz Joseph Muller">Franz Joseph Muller</a> produced the same metal oxide and could not identify it. In 1795, chemist <a href="/wiki/Martin_Heinrich_Klaproth" title="Martin Heinrich Klaproth">Martin Heinrich Klaproth</a> independently rediscovered the metal oxide in <a href="/wiki/Rutile" title="Rutile">rutile</a> from the Hungarian village Boinik.<sup id="cite_ref-Emsley2001p452_3-1" class="reference"><a href="#cite_note-Emsley2001p452-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> He identified the oxide containing a new element and named it for the <a href="/wiki/Titan_(mythology)" class="mw-redirect" title="Titan (mythology)">Titans</a> of <a href="/wiki/Greek_mythology" title="Greek mythology">Greek mythology</a>.<sup id="cite_ref-weeksIII_5-0" class="reference"><a href="#cite_note-weeksIII-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> Berzelius was also the first to prepare titanium metal (albeit impurely), doing so in 1825.<sup id="cite_ref-Greenwood954_6-0" class="reference"><a href="#cite_note-Greenwood954-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>The <a href="/wiki/X-ray_spectroscopy" title="X-ray spectroscopy">X-ray spectroscopy</a> done by <a href="/wiki/Henry_Moseley" title="Henry Moseley">Henry Moseley</a> in 1914 showed a direct dependency between <a href="/wiki/Spectral_line" title="Spectral line">spectral line</a> and <a href="/wiki/Effective_nuclear_charge" title="Effective nuclear charge">effective nuclear charge</a>. This led to the nuclear charge, or <a href="/wiki/Atomic_number" title="Atomic number">atomic number</a> of an element, being used to ascertain its place within the periodic table. With this method, Moseley determined the number of <a href="/wiki/Lanthanides" class="mw-redirect" title="Lanthanides">lanthanides</a> and showed that there was a missing element with atomic number 72.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> This spurred chemists to look for it.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Georges_Urbain" title="Georges Urbain">Georges Urbain</a> asserted that he found element 72 in the <a href="/wiki/Rare_earth_element" class="mw-redirect" title="Rare earth element">rare earth elements</a> in 1907 and published his results on <i>celtium</i> in 1911.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> Neither the spectra nor the chemical behavior he claimed matched with the element found later, and therefore his claim was turned down after a long-standing controversy.<sup id="cite_ref-Mel_10-0" class="reference"><a href="#cite_note-Mel-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p><p>By early 1923, several physicists and chemists such as <a href="/wiki/Niels_Bohr" title="Niels Bohr">Niels Bohr</a><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> and <a href="/wiki/Charles_Rugeley_Bury" title="Charles Rugeley Bury">Charles Rugeley Bury</a><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> suggested that element 72 should resemble zirconium and therefore was not part of the rare earth elements group. These suggestions were based on Bohr's theories of the atom, the X-ray spectroscopy of Moseley, and the chemical arguments of <a href="/wiki/Friedrich_Paneth" title="Friedrich Paneth">Friedrich Paneth</a>.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> Encouraged by this, and by the reappearance in 1922 of Urbain's claims that element 72 was a rare earth element discovered in 1911, <a href="/wiki/Dirk_Coster" title="Dirk Coster">Dirk Coster</a> and <a href="/wiki/Georg_von_Hevesy" class="mw-redirect" title="Georg von Hevesy">Georg von Hevesy</a> were motivated to search for the new element in zirconium ores.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Hafnium" title="Hafnium">Hafnium</a> was discovered by the two in 1923 in Copenhagen, Denmark.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> The place where the discovery took place led to the element being named for the Latin name for "Copenhagen", <i>Hafnia</i>, the home town of <a href="/wiki/Niels_Bohr" title="Niels Bohr">Niels Bohr</a>.<sup id="cite_ref-Scerri_18-0" class="reference"><a href="#cite_note-Scerri-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>Hafnium was separated from zirconium through repeated recrystallization of the double <a href="/wiki/Ammonium" title="Ammonium">ammonium</a> or <a href="/wiki/Potassium" title="Potassium">potassium</a> fluorides by <a href="/w/index.php?title=Valdemar_Thal_Jantzen&action=edit&redlink=1" class="new" title="Valdemar Thal Jantzen (page does not exist)">Valdemar Thal Jantzen</a> and von Hevesy.<sup id="cite_ref-Ark1924a_19-0" class="reference"><a href="#cite_note-Ark1924a-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Anton_Eduard_van_Arkel" title="Anton Eduard van Arkel">Anton Eduard van Arkel</a> and <a href="/wiki/Jan_Hendrik_de_Boer" title="Jan Hendrik de Boer">Jan Hendrik de Boer</a> were the first to prepare metallic hafnium by passing hafnium tetraiodide vapor over a heated <a href="/wiki/Tungsten" title="Tungsten">tungsten</a> filament in 1924.<sup id="cite_ref-Ark1924b_20-0" class="reference"><a href="#cite_note-Ark1924b-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Ark1925_21-0" class="reference"><a href="#cite_note-Ark1925-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> The long delay between the discovery of the lightest two group 4 elements and that of hafnium was partly due to the rarity of hafnium, and partly due to the extreme similarity of zirconium and hafnium, so that all previous samples of zirconium had in reality been contaminated with hafnium without anyone knowing.<sup id="cite_ref-EncyChem_22-0" class="reference"><a href="#cite_note-EncyChem-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p><p>The last element of the group, <a href="/wiki/Rutherfordium" title="Rutherfordium">rutherfordium</a>, does not occur naturally and had to be made by synthesis. The first reported detection was by a team at the <a href="/wiki/Joint_Institute_for_Nuclear_Research" title="Joint Institute for Nuclear Research">Joint Institute for Nuclear Research</a> (JINR), which in 1964 claimed to have produced the new element by bombarding a <a href="/wiki/Plutonium" title="Plutonium">plutonium</a>-242 target with <a href="/wiki/Neon" title="Neon">neon</a>-22 ions, although this was later put into question.<sup id="cite_ref-93TWG_23-0" class="reference"><a href="#cite_note-93TWG-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> More conclusive evidence was obtained by researchers at the <a href="/wiki/University_of_California,_Berkeley" title="University of California, Berkeley">University of California, Berkeley</a>, who synthesised element 104 in 1969 by bombarding a <a href="/wiki/Californium" title="Californium">californium</a>-249 target with <a href="/wiki/Carbon-12" title="Carbon-12">carbon-12</a> ions.<sup id="cite_ref-69Gh01_24-0" class="reference"><a href="#cite_note-69Gh01-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> A <a href="/wiki/Transfermium_Wars" title="Transfermium Wars">controversy</a> erupted on who had discovered the element, which each group suggesting its own name: the Dubna group named the element <i>kurchatovium</i> after <a href="/wiki/Igor_Kurchatov" title="Igor Kurchatov">Igor Kurchatov</a>, while the Berkeley group named it <i>rutherfordium</i> after <a href="/wiki/Ernest_Rutherford" title="Ernest Rutherford">Ernest Rutherford</a>.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> Eventually a joint working party of <a href="/wiki/IUPAC" class="mw-redirect" title="IUPAC">IUPAC</a> and <a href="/wiki/IUPAP" class="mw-redirect" title="IUPAP">IUPAP</a>, the Transfermium Working Group, decided that credit for the discovery should be shared. After various compromises were attempted, in 1997 IUPAC officially named the element rutherfordium following the American proposal.<sup id="cite_ref-97IUPAC_26-0" class="reference"><a href="#cite_note-97IUPAC-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Characteristics">Characteristics</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=2" title="Edit section: Characteristics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Chemical">Chemical</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=3" title="Edit section: Chemical"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable" style="float:right; font-size:95%;"> <caption> </caption> <tbody><tr> <th colspan="4"><a href="/wiki/Electron_configuration" title="Electron configuration">Electron configurations</a> of the group 4 elements </th></tr> <tr> <th><abbr title="Atomic number"><i>Z</i></abbr></th> <th>Element</th> <th colspan="2">Electron configuration </th></tr> <tr> <td style="text-align:right">22</td> <td>Ti, titanium</td> <td><style data-mw-deduplicate="TemplateStyles:r886049734">.mw-parser-output .monospaced{font-family:monospace,monospace}</style><span class="monospaced">2, 8, 10,  2</span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">[Ar]   <sup>  </sup> 3d<sup>2</sup> 4s<sup>2</sup></span> </td></tr> <tr> <td style="text-align:right">40</td> <td>Zr, zirconium</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">2, 8, 18, 10,  2</span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">[Kr]   <sup>  </sup> 4d<sup>2</sup> 5s<sup>2</sup></span> </td></tr> <tr> <td style="text-align:right">72</td> <td>Hf, hafnium</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">2, 8, 18, 32, 10,  2</span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">[Xe] 4f<sup>14</sup> 5d<sup>2</sup> 6s<sup>2</sup></span> </td></tr> <tr> <td style="text-align:right">104</td> <td>Rf, rutherfordium</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">2, 8, 18, 32, 32, 10, 2</span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886049734"><span class="monospaced">[Rn] 5f<sup>14</sup> 6d<sup>2</sup> 7s<sup>2</sup></span> </td></tr></tbody></table> <p>Like other groups, the members of this family show patterns in their electron configurations, especially the outermost shells, resulting in trends in chemical behavior. Most of the chemistry has been observed only for the first three members of the group; chemical properties of rutherfordium are not well-characterized, but what is known and predicted matches its position as a heavier homolog of hafnium.<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p><p>Titanium, zirconium, and hafnium are reactive metals, but this is masked in the bulk form because they form a dense oxide layer that sticks to the metal and reforms even if removed. As such, the bulk metals are very resistant to chemical attack; most aqueous acids have no effect unless heated, and aqueous alkalis have no effect even when hot. Oxidizing acids such as <a href="/wiki/Nitric_acid" title="Nitric acid">nitric acids</a> indeed tend to reduce reactivity as they induce the formation of this oxide layer. The exception is <a href="/wiki/Hydrofluoric_acid" title="Hydrofluoric acid">hydrofluoric acid</a>, as it forms soluble fluoro complexes of the metals. When finely divided, their reactivity shows as they become <a href="/wiki/Pyrophoricity" title="Pyrophoricity">pyrophoric</a>, directly reacting with <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> and <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a>, and even <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a> in the case of titanium. All three are fairly electropositive, although less so than their predecessors in <a href="/wiki/Group_3_element" title="Group 3 element">group 3</a>.<sup id="cite_ref-Greenwood958_28-0" class="reference"><a href="#cite_note-Greenwood958-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> The oxides <a href="/wiki/Titanium_dioxide" title="Titanium dioxide">TiO<sub>2</sub></a>, <a href="/wiki/Zirconium_dioxide" title="Zirconium dioxide">ZrO<sub>2</sub></a> and <a href="/wiki/Hafnium(IV)_oxide" title="Hafnium(IV) oxide">HfO<sub>2</sub></a> are white solids with high melting points and unreactive against most acids.<sup id="cite_ref-Holl_29-0" class="reference"><a href="#cite_note-Holl-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p><p>The chemistry of group 4 elements is dominated by the group oxidation state. Zirconium and hafnium are in particular extremely similar, with the most salient differences being physical rather than chemical (melting and boiling points of compounds and their solubility in solvents).<sup id="cite_ref-Holl_29-1" class="reference"><a href="#cite_note-Holl-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> This is an effect of the <a href="/wiki/Lanthanide_contraction" title="Lanthanide contraction">lanthanide contraction</a>: the expected increase of atomic radius from the 4d to the 5d elements is wiped out by the insertion of the 4f elements before. Titanium, being smaller, is distinct from these two: its oxide is less basic than those of zirconium and hafnium, and its aqueous chemistry is more hydrolyzed.<sup id="cite_ref-Greenwood958_28-1" class="reference"><a href="#cite_note-Greenwood958-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> Rutherfordium should have a still more basic oxide than zirconium and hafnium.<sup id="cite_ref-primefan_30-0" class="reference"><a href="#cite_note-primefan-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p><p>The chemistry of all three is dominated by the +4 oxidation state, though this is too high to be well-described as totally ionic. Low oxidation states are not well-represented for zirconium and hafnium<sup id="cite_ref-Greenwood958_28-2" class="reference"><a href="#cite_note-Greenwood958-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> (and should be even less well-represented for rutherfordium);<sup id="cite_ref-primefan_30-1" class="reference"><a href="#cite_note-primefan-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> the +3 oxidation state of zirconium and hafnium reduces water. For titanium, this oxidation state is merely easily oxidised, forming a violet Ti<sup>3+</sup> aqua cation in solution. The elements have a significant coordination chemistry: zirconium and hafnium are large enough to readily support the coordination number of 8. All three metals however form weak sigma bonds to carbon and because they have few d electrons, <a href="/wiki/Pi_backbonding" title="Pi backbonding">pi backbonding</a> is not very effective either.<sup id="cite_ref-Greenwood958_28-3" class="reference"><a href="#cite_note-Greenwood958-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Physical">Physical</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=4" title="Edit section: Physical"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The trends in group 4 follow those of the other early d-block groups and reflect the addition of a filled f-shell into the core in passing from the fifth to the sixth period. All the stable members of the group are silvery <a href="/wiki/Refractory_metal" class="mw-redirect" title="Refractory metal">refractory metals</a>, though impurities of <a href="/wiki/Carbon" title="Carbon">carbon</a>, <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, and oxygen make them brittle.<sup id="cite_ref-Greenwood956_31-0" class="reference"><a href="#cite_note-Greenwood956-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> They all crystallize in the <a href="/wiki/Hexagonal_close-packed" class="mw-redirect" title="Hexagonal close-packed">hexagonal close-packed</a> structure at room temperature,<sup id="cite_ref-Greenwood946_32-0" class="reference"><a href="#cite_note-Greenwood946-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> and rutherfordium is expected to do the same.<sup id="cite_ref-hcp_33-0" class="reference"><a href="#cite_note-hcp-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> At high temperatures, titanium, zirconium, and hafnium transform to a <a href="/wiki/Body-centered_cubic" class="mw-redirect" title="Body-centered cubic">body-centered cubic</a> structure. While they are better conductors of heat and electricity than their group 3 predecessors, they are still poor compared to most metals. This, along with the higher melting and boiling points, and enthalpies of fusion, vaporization, and atomization, reflects the extra d electron available for metallic bonding.<sup id="cite_ref-Greenwood946_32-1" class="reference"><a href="#cite_note-Greenwood946-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> </p><p>The table below is a summary of the key physical properties of the group 4 elements. The four question-marked values are extrapolated.<sup id="cite_ref-Haire_34-0" class="reference"><a href="#cite_note-Haire-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable centered" style="text-align:center;"> <caption>Properties of the group 4 elements </caption> <tbody><tr> <th>Name </th> <th>Ti, <a href="/wiki/Titanium" title="Titanium">titanium</a> </th> <th>Zr, <a href="/wiki/Zirconium" title="Zirconium">zirconium</a> </th> <th>Hf, <a href="/wiki/Hafnium" title="Hafnium">hafnium</a> </th> <th>Rf, <a href="/wiki/Rutherfordium" title="Rutherfordium">rutherfordium</a> </th></tr> <tr> <td style="background:lightgrey; text-align:left;"><a href="/wiki/Melting_point" title="Melting point">Melting point</a> </td> <td>1941 K (1668 °C)</td> <td>2130 K (1857 °C)</td> <td>2506 K (2233 °C)</td> <td>2400 K (2100 °C)? </td></tr> <tr> <td style="background:lightgrey; text-align:left;"><a href="/wiki/Boiling_point" title="Boiling point">Boiling point</a> </td> <td>3560 K (3287 °C)</td> <td>4682 K (4409 °C)</td> <td>4876 K (4603 °C)</td> <td>5800 K (5500 °C)? </td></tr> <tr> <td style="background:lightgrey; text-align:left;"><a href="/wiki/Density" title="Density">Density</a> </td> <td>4.507 g·cm<sup>−3</sup></td> <td>6.511 g·cm<sup>−3</sup></td> <td>13.31 g·cm<sup>−3</sup></td> <td>17 g·cm<sup>−3</sup>? </td></tr> <tr> <td style="background:lightgrey; text-align:left;">Appearance </td> <td>silver metallic</td> <td>silver white</td> <td>silver gray</td> <td>? </td></tr> <tr> <td style="background:lightgrey; text-align:left;"><a href="/wiki/Atomic_radius" title="Atomic radius">Atomic radius</a> </td> <td>140 pm</td> <td>155 pm</td> <td>155 pm</td> <td>150 pm? </td></tr></tbody></table> <div class="mw-heading mw-heading4"><h4 id="Titanium">Titanium</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=5" title="Edit section: Titanium"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable relarticle mainarticle selfreference noprint">This section is <a href="/wiki/Help:Transclusion" title="Help:Transclusion">transcluded</a> from <a href="/wiki/Titanium" title="Titanium">Titanium</a>. <span class="plainlinks" style="font-style: normal; font-size:85%;">(<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Titanium&action=edit">edit</a> | <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Titanium&action=history">history</a>)</span></div> <p>As a <a href="/wiki/Metal" title="Metal">metal</a>, titanium is recognized for its high <a href="/wiki/Strength-to-weight_ratio" class="mw-redirect" title="Strength-to-weight ratio">strength-to-weight ratio</a>.<sup id="cite_ref-TICE6th_35-0" class="reference"><a href="#cite_note-TICE6th-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> It is a strong metal with low <a href="/wiki/Density" title="Density">density</a> that is quite <a href="/wiki/Ductility" title="Ductility">ductile</a> (especially in an <a href="/wiki/Oxygen" title="Oxygen">oxygen</a>-free environment),<sup id="cite_ref-EBC_36-0" class="reference"><a href="#cite_note-EBC-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> lustrous, and metallic-white in <a href="/wiki/Color" title="Color">color</a>.<sup id="cite_ref-Stwertka1998_37-0" class="reference"><a href="#cite_note-Stwertka1998-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> Due to its relatively high melting point (1,668 °C or 3,034 °F) it has sometimes been described as a <a href="/wiki/Refractory_metals" title="Refractory metals">refractory metal</a>, but this is not the case.<sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> It is <a href="/wiki/Paramagnetism" title="Paramagnetism">paramagnetic</a> and has fairly low <a href="/wiki/Electrical_conductivity" class="mw-redirect" title="Electrical conductivity">electrical</a> and <a href="/wiki/Thermal_conductivity" class="mw-redirect" title="Thermal conductivity">thermal conductivity</a> compared to other metals.<sup id="cite_ref-EBC_36-1" class="reference"><a href="#cite_note-EBC-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> Titanium is <a href="/wiki/Superconductivity" title="Superconductivity">superconducting</a> when cooled below its critical temperature of 0.49 K.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Zirconium">Zirconium</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=6" title="Edit section: Zirconium"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable relarticle mainarticle selfreference noprint">This section is <a href="/wiki/Help:Transclusion" title="Help:Transclusion">transcluded</a> from <a href="/wiki/Zirconium" title="Zirconium">Zirconium</a>. <span class="plainlinks" style="font-style: normal; font-size:85%;">(<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Zirconium&action=edit">edit</a> | <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Zirconium&action=history">history</a>)</span></div> <p>Zirconium is a <a href="/wiki/Luster_(mineralogy)" class="mw-redirect" title="Luster (mineralogy)">lustrous</a>, greyish-white, soft, ductile, malleable metal that is solid at room temperature, though it is hard and <a href="/wiki/Brittle" class="mw-redirect" title="Brittle">brittle</a> at lesser purities.<sup id="cite_ref-nbb_2-1" class="reference"><a href="#cite_note-nbb-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> In powder form, zirconium is highly flammable, but the solid form is much less prone to ignition. Zirconium is highly resistant to corrosion by alkalis, acids, salt water and other agents.<sup id="cite_ref-CRC2008_1-2" class="reference"><a href="#cite_note-CRC2008-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> However, it will dissolve in <a href="/wiki/Hydrochloric_acid" title="Hydrochloric acid">hydrochloric</a> and <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a>, especially when <a href="/wiki/Fluorine" title="Fluorine">fluorine</a> is present.<sup id="cite_ref-Nostrand_41-0" class="reference"><a href="#cite_note-Nostrand-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Alloy" title="Alloy">Alloys</a> with <a href="/wiki/Zinc" title="Zinc">zinc</a> are <a href="/wiki/Magnetism" title="Magnetism">magnetic</a> at less than 35 K.<sup id="cite_ref-CRC2008_1-3" class="reference"><a href="#cite_note-CRC2008-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Hafnium">Hafnium</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=7" title="Edit section: Hafnium"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable relarticle mainarticle selfreference noprint">This section is <a href="/wiki/Help:Transclusion" title="Help:Transclusion">transcluded</a> from <a href="/wiki/Hafnium" title="Hafnium">Hafnium</a>. <span class="plainlinks" style="font-style: normal; font-size:85%;">(<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Hafnium&action=edit">edit</a> | <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Hafnium&action=history">history</a>)</span></div> <p>Hafnium is a shiny, silvery, <a href="/wiki/Ductility" title="Ductility">ductile</a> <a href="/wiki/Metal" title="Metal">metal</a> that is <a href="/wiki/Corrosion" title="Corrosion">corrosion</a>-resistant and chemically similar to zirconium<sup id="cite_ref-ASTM_42-0" class="reference"><a href="#cite_note-ASTM-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> in that they have the same number of <a href="/wiki/Valence_electron" title="Valence electron">valence electrons</a> and are in the same group. Also, their <a href="/wiki/Relativistic_quantum_chemistry" title="Relativistic quantum chemistry">relativistic effects</a> are similar: The expected expansion of atomic radii from period 5 to 6 is almost exactly canceled out by the <a href="/wiki/Lanthanide_contraction" title="Lanthanide contraction">lanthanide contraction</a>. Hafnium changes from its alpha form, a hexagonal close-packed lattice, to its beta form, a body-centered cubic lattice, at 2388 K.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> The physical properties of hafnium metal samples are markedly affected by zirconium impurities, especially the nuclear properties, as these two elements are among the most difficult to separate because of their chemical similarity.<sup id="cite_ref-ASTM_42-1" class="reference"><a href="#cite_note-ASTM-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Rutherfordium">Rutherfordium</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=8" title="Edit section: Rutherfordium"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable relarticle mainarticle selfreference noprint">This section is <a href="/wiki/Help:Transclusion" title="Help:Transclusion">transcluded</a> from <a href="/wiki/Rutherfordium" title="Rutherfordium">Rutherfordium</a>. <span class="plainlinks" style="font-style: normal; font-size:85%;">(<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Rutherfordium&action=edit">edit</a> | <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Rutherfordium&action=history">history</a>)</span></div> <p>Rutherfordium is expected to be a solid under normal conditions and have a <a href="/wiki/Hexagonal_close-packed" class="mw-redirect" title="Hexagonal close-packed">hexagonal close-packed</a> crystal structure (<sup><i>c</i></sup>/<sub><i>a</i></sub> = 1.61), similar to its lighter <a href="/wiki/Congener_(chemistry)" title="Congener (chemistry)">congener</a> hafnium.<sup id="cite_ref-hcp_33-1" class="reference"><a href="#cite_note-hcp-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> It should be a metal with <a href="/wiki/Density" title="Density">density</a> ~17 g/cm<sup>3</sup>.<sup id="cite_ref-density_44-0" class="reference"><a href="#cite_note-density-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-kratz_45-0" class="reference"><a href="#cite_note-kratz-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> The atomic radius of rutherfordium is expected to be ~150 <a href="/wiki/Picometer" class="mw-redirect" title="Picometer">pm</a>. Due to relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, Rf<sup>+</sup> and Rf<sup>2+</sup> ions are predicted to give up 6d electrons instead of 7s electrons, which is the opposite of the behavior of its lighter homologs.<sup id="cite_ref-Haire_34-1" class="reference"><a href="#cite_note-Haire-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> When under high pressure (variously calculated as 72 or ~50 <a href="/wiki/Gigapascal" class="mw-redirect" title="Gigapascal">GPa</a>), rutherfordium is expected to transition to <a href="/wiki/Body-centered_cubic" class="mw-redirect" title="Body-centered cubic">body-centered cubic</a> crystal structure; hafnium transforms to this structure at 71±1 GPa, but has an intermediate ω structure that it transforms to at 38±8 GPa that should be lacking for rutherfordium.<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Production">Production</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=9" title="Edit section: Production"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The production of the metals itself is difficult due to their reactivity. The formation of <a href="/wiki/Oxide" title="Oxide">oxides</a>, <a href="/wiki/Nitride" title="Nitride">nitrides</a>, and <a href="/wiki/Carbide" title="Carbide">carbides</a> must be avoided to yield workable metals; this is normally achieved by the <a href="/wiki/Kroll_process" title="Kroll process">Kroll process</a>. The oxides (MO<sub>2</sub>) are reacted with <a href="/wiki/Coal" title="Coal">coal</a> and <a href="/wiki/Chlorine" title="Chlorine">chlorine</a> to form the chlorides (MCl<sub>4</sub>). The chlorides of the metals are then reacted with magnesium, yielding <a href="/wiki/Magnesium_chloride" title="Magnesium chloride">magnesium chloride</a> and the metals. </p><p>Further purification is done by a <a href="/wiki/Chemical_transport_reaction" title="Chemical transport reaction">chemical transport reaction</a> developed by <a href="/wiki/Anton_Eduard_van_Arkel" title="Anton Eduard van Arkel">Anton Eduard van Arkel</a> and <a href="/wiki/Jan_Hendrik_de_Boer" title="Jan Hendrik de Boer">Jan Hendrik de Boer</a>. In a closed vessel, the metal reacts with <a href="/wiki/Iodine" title="Iodine">iodine</a> at temperatures above 500 °C forming metal(IV) iodide; at a tungsten filament of nearly 2000 °C the reverse reaction happens and the iodine and metal are set free. The metal forms a solid coating on the tungsten filament and the iodine can react with additional metal resulting in a steady turnover.<sup id="cite_ref-Holl_29-2" class="reference"><a href="#cite_note-Holl-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Ark1925_21-1" class="reference"><a href="#cite_note-Ark1925-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><dl><dd>M + 2 I<sub>2</sub> (low temp.) → MI<sub>4</sub></dd> <dd>MI<sub>4</sub> (high temp.) → M + 2 I<sub>2</sub></dd></dl></dd></dl> <div class="mw-heading mw-heading2"><h2 id="Occurrence">Occurrence</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=10" title="Edit section: Occurrence"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:HeavyMineralsBeachSand.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/81/HeavyMineralsBeachSand.jpg/220px-HeavyMineralsBeachSand.jpg" decoding="async" width="220" height="151" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/81/HeavyMineralsBeachSand.jpg/330px-HeavyMineralsBeachSand.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/81/HeavyMineralsBeachSand.jpg/440px-HeavyMineralsBeachSand.jpg 2x" data-file-width="2000" data-file-height="1370" /></a><figcaption>Heavy minerals (dark) in a quartz beach sand (<a href="/wiki/Chennai" title="Chennai">Chennai</a>, India).</figcaption></figure> <p>The abundance of the group 4 metals decreases with increase of atomic mass. Titanium is the seventh most abundant metal in Earth's crust and has an abundance of 6320 ppm, while zirconium has an abundance of 162 ppm and hafnium has only an abundance of 3 ppm.<sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> </p><p>All three stable elements occur in <a href="/wiki/Heavy_mineral_sands_ore_deposits" title="Heavy mineral sands ore deposits">heavy mineral sands ore deposits</a>, which are <a href="/wiki/Placer_deposit" title="Placer deposit">placer deposits</a> formed, most usually in <a href="/wiki/Beach" title="Beach">beach</a> environments, by concentration due to the <a href="/wiki/Specific_gravity" class="mw-redirect" title="Specific gravity">specific gravity</a> of the mineral grains of erosion material from <a href="/wiki/Mafic" title="Mafic">mafic</a> and <a href="/wiki/Ultramafic_rock" title="Ultramafic rock">ultramafic rock</a>. The titanium minerals are mostly <a href="/wiki/Anatase" title="Anatase">anatase</a> and <a href="/wiki/Rutile" title="Rutile">rutile</a>, and zirconium occurs in the mineral <a href="/wiki/Zircon" title="Zircon">zircon</a>. Because of the chemical similarity, up to 5% of the zirconium in zircon is replaced by hafnium. The largest producers of the group 4 elements are <a href="/wiki/Australia" title="Australia">Australia</a>, <a href="/wiki/South_Africa" title="South Africa">South Africa</a> and <a href="/wiki/Canada" title="Canada">Canada</a>.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-usgs2008_49-0" class="reference"><a href="#cite_note-usgs2008-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-usgypTi2009_51-0" class="reference"><a href="#cite_note-usgypTi2009-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-usgcomTi2009_52-0" class="reference"><a href="#cite_note-usgcomTi2009-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Applications">Applications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=11" title="Edit section: Applications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Titanium metal and its alloys have a wide range of applications, where the corrosion resistance, the heat stability and the low density (light weight) are of benefit. The foremost use of corrosion-resistant hafnium and zirconium has been in nuclear reactors. Zirconium has a very low and hafnium has a high <a href="/wiki/Neutron_capture" title="Neutron capture">thermal neutron-capture cross-section</a>. Therefore, zirconium (mostly as <a href="/wiki/Zircaloy" class="mw-redirect" title="Zircaloy">zircaloy</a>) is used as <a href="/wiki/Cladding_(metalworking)" title="Cladding (metalworking)">cladding</a> of <a href="/wiki/Fuel_rod" class="mw-redirect" title="Fuel rod">fuel rods</a> in <a href="/wiki/Nuclear_reactor" title="Nuclear reactor">nuclear reactors</a>,<sup id="cite_ref-ASTM_42-2" class="reference"><a href="#cite_note-ASTM-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> while hafnium is used in <a href="/wiki/Control_rod" title="Control rod">control rods</a> for <a href="/wiki/Nuclear_reactor" title="Nuclear reactor">nuclear reactors</a>, because each hafnium atom can absorb multiple neutrons.<sup id="cite_ref-Hend_53-0" class="reference"><a href="#cite_note-Hend-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup> </p><p>Smaller amounts of hafnium<sup id="cite_ref-hightemp_55-0" class="reference"><a href="#cite_note-hightemp-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup> and zirconium are used in super alloys to improve the properties of those alloys.<sup id="cite_ref-Super_56-0" class="reference"><a href="#cite_note-Super-56"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Biological_occurrences">Biological occurrences</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=12" title="Edit section: Biological occurrences"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <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-Expand_section plainlinks metadata ambox mbox-small-left ambox-content" role="presentation"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><a href="/wiki/File:Wiki_letter_w_cropped.svg" class="mw-file-description"><img alt="[icon]" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/20px-Wiki_letter_w_cropped.svg.png" decoding="async" width="20" height="14" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/30px-Wiki_letter_w_cropped.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Wiki_letter_w_cropped.svg/40px-Wiki_letter_w_cropped.svg.png 2x" data-file-width="44" data-file-height="31" /></a></span></td><td class="mbox-text"><div class="mbox-text-span">This section <b>needs expansion</b>. You can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Group_4_element&action=edit&section=">adding to it</a>. <span class="date-container"><i>(<span class="date">February 2022</span>)</i></span></div></td></tr></tbody></table> <p>The group 4 elements are hard refractory metals with low aqueous solubility and low availability to the biosphere. Titanium and zirconium are relatively abundant, whereas hafnium and rutherfordium are rare to non-existent in the environment. </p><p>Titanium has no known role in any organism's biology. However, many studies suggest that titanium could be biologically active. Most titanium on Earth is stored within insoluble minerals, so it is unlikely to be a part of any biological system in spite of being potentially biologically active.<sup id="cite_ref-57" class="reference"><a href="#cite_note-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> </p><p>Zirconium plays no known role in any biological system,<sup id="cite_ref-58" class="reference"><a href="#cite_note-58"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup> but is common in biological systems. Certain antiperspirant products use <a href="/wiki/Aluminium_zirconium_tetrachlorohydrex_gly" title="Aluminium zirconium tetrachlorohydrex gly">Aluminium zirconium tetrachlorohydrex gly</a> to block sweat pores in the skin.<sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span class="cite-bracket">[</span>59<span class="cite-bracket">]</span></a></sup> </p><p>Hafnium plays no known role in any biological system, and has low toxicity.<sup id="cite_ref-60" class="reference"><a href="#cite_note-60"><span class="cite-bracket">[</span>60<span class="cite-bracket">]</span></a></sup> </p><p>Rutherfordium is synthetic, expensive, and radioactive: the most stable isotopes have half-lives under an hour. Few chemical properties and no biological functions are known. </p> <div class="mw-heading mw-heading2"><h2 id="Precautions">Precautions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=13" title="Edit section: Precautions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Titanium is non-toxic even in large doses and does not play any natural role inside the <a href="/wiki/Human_body" title="Human body">human body</a>.<sup id="cite_ref-Emsley2001_61-0" class="reference"><a href="#cite_note-Emsley2001-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> An estimated quantity of 0.8 milligrams of titanium is ingested by humans each day, but most passes through without being absorbed in the tissues.<sup id="cite_ref-Emsley2001_61-1" class="reference"><a href="#cite_note-Emsley2001-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup> It does, however, sometimes <a href="/wiki/Bioaccumulation" title="Bioaccumulation">bio-accumulate</a> in tissues that contain <a href="/wiki/Silica" class="mw-redirect" title="Silica">silica</a>. One study indicates a possible connection between titanium and <a href="/wiki/Yellow_nail_syndrome" title="Yellow nail syndrome">yellow nail syndrome</a>.<sup id="cite_ref-62" class="reference"><a href="#cite_note-62"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup> </p><p>Zirconium powder can cause irritation, but only contact with the eyes requires medical attention.<sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span class="cite-bracket">[</span>63<span class="cite-bracket">]</span></a></sup> OSHA recommendations for zirconium are 5 mg/m<sup>3</sup> <a href="/wiki/Permissible_exposure_limit" title="Permissible exposure limit">time weighted average</a> limit and a 10 mg/m<sup>3</sup> short-term exposure limit.<sup id="cite_ref-64" class="reference"><a href="#cite_note-64"><span class="cite-bracket">[</span>64<span class="cite-bracket">]</span></a></sup> </p><p>Only limited data exists on the toxicology of hafnium.<sup id="cite_ref-hafniumtox_65-0" class="reference"><a href="#cite_note-hafniumtox-65"><span class="cite-bracket">[</span>65<span class="cite-bracket">]</span></a></sup> Care needs to be taken when <a href="/wiki/Machining" title="Machining">machining</a> hafnium because it is <a href="/wiki/Pyrophoric" class="mw-redirect" title="Pyrophoric">pyrophoric</a>—fine particles can spontaneously combust when exposed to air. Compounds that contain this metal are rarely encountered by most people. The pure metal is not considered toxic, but hafnium compounds should be handled as if they were toxic because the ionic forms of metals are normally at greatest risk for toxicity, and limited animal testing has been done for hafnium compounds.<sup id="cite_ref-hafniumtox_65-1" class="reference"><a href="#cite_note-hafniumtox-65"><span class="cite-bracket">[</span>65<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=14" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-CRC2008-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-CRC2008_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-CRC2008_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-CRC2008_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-CRC2008_1-3"><sup><i><b>d</b></i></sup></a></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="CITEREFLide2007–2008" class="citation book cs1">Lide, David R., ed. (2007–2008). "Zirconium". <i>CRC Handbook of Chemistry and Physics</i>. Vol. 4. New York: CRC Press. p. 42. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8493-0488-0" title="Special:BookSources/978-0-8493-0488-0"><bdi>978-0-8493-0488-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Zirconium&rft.btitle=CRC+Handbook+of+Chemistry+and+Physics&rft.place=New+York&rft.pages=42&rft.pub=CRC+Press&rft.date=2007%2F2008&rft.isbn=978-0-8493-0488-0&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-nbb-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-nbb_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-nbb_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFEmsley2001">Emsley 2001</a>, pp. 506–510</span> </li> <li id="cite_note-Emsley2001p452-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-Emsley2001p452_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Emsley2001p452_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFEmsley2001">Emsley 2001</a>, p. 452</span> </li> <li id="cite_note-Barksdale1968p732-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-Barksdale1968p732_4-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBarksdale1968">Barksdale 1968</a>, p. 732</span> </li> <li id="cite_note-weeksIII-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-weeksIII_5-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWeeks1932" class="citation journal cs1"><a href="/wiki/Mary_Elvira_Weeks" title="Mary Elvira Weeks">Weeks, Mary Elvira</a> (1932). "III. Some Eighteenth-Century Metals". <i>Journal of Chemical Education</i>. <b>9</b> (7): 1231–1243. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1932JChEd...9.1231W">1932JChEd...9.1231W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fed009p1231">10.1021/ed009p1231</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=III.+Some+Eighteenth-Century+Metals&rft.volume=9&rft.issue=7&rft.pages=1231-1243&rft.date=1932&rft_id=info%3Adoi%2F10.1021%2Fed009p1231&rft_id=info%3Abibcode%2F1932JChEd...9.1231W&rft.aulast=Weeks&rft.aufirst=Mary+Elvira&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-Greenwood954-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood954_6-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, p. 954</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeilbron1966" class="citation journal cs1">Heilbron, John L. (1966). "The Work of H. G. J. Moseley". <i>Isis</i>. <b>57</b> (3): 336. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F350143">10.1086/350143</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:144765815">144765815</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Isis&rft.atitle=The+Work+of+H.+G.+J.+Moseley&rft.volume=57&rft.issue=3&rft.pages=336&rft.date=1966&rft_id=info%3Adoi%2F10.1086%2F350143&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A144765815%23id-name%3DS2CID&rft.aulast=Heilbron&rft.aufirst=John+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeimann1967" class="citation journal cs1">Heimann, P. M. (1967). "Moseley and celtium: The search for a missing element". <i><a href="/wiki/Annals_of_Science" title="Annals of Science">Annals of Science</a></i>. <b>23</b> (4): 249–260. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F00033796700203306">10.1080/00033796700203306</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annals+of+Science&rft.atitle=Moseley+and+celtium%3A+The+search+for+a+missing+element&rft.volume=23&rft.issue=4&rft.pages=249-260&rft.date=1967&rft_id=info%3Adoi%2F10.1080%2F00033796700203306&rft.aulast=Heimann&rft.aufirst=P.+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUrbain1911" class="citation journal cs1 cs1-prop-foreign-lang-source">Urbain, M. G. (1911). <a rel="nofollow" class="external text" href="http://gallica.bnf.fr/ark:/12148/bpt6k3105c/f141.table">"Sur un nouvel élément qui accompagne le lutécium et le scandium dans les terres de la gadolinite: le celtium (On a new element that accompanies lutetium and scandium in gadolinite: celtium)"</a>. <i>Comptes Rendus</i> (in French): 141<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-09-10</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Comptes+Rendus&rft.atitle=Sur+un+nouvel+%C3%A9l%C3%A9ment+qui+accompagne+le+lut%C3%A9cium+et+le+scandium+dans+les+terres+de+la+gadolinite%3A+le+celtium+%28On+a+new+element+that+accompanies+lutetium+and+scandium+in+gadolinite%3A+celtium%29&rft.pages=141&rft.date=1911&rft.aulast=Urbain&rft.aufirst=M.+G.&rft_id=http%3A%2F%2Fgallica.bnf.fr%2Fark%3A%2F12148%2Fbpt6k3105c%2Ff141.table&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-Mel-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-Mel_10-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMel'nikov1982" class="citation journal cs1">Mel'nikov, V. P. (1982). "Some Details in the Prehistory of the Discovery of Element 72". <i>Centaurus</i>. <b>26</b> (3): 317–322. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1982Cent...26..317M">1982Cent...26..317M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1600-0498.1982.tb00667.x">10.1111/j.1600-0498.1982.tb00667.x</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Centaurus&rft.atitle=Some+Details+in+the+Prehistory+of+the+Discovery+of+Element+72&rft.volume=26&rft.issue=3&rft.pages=317-322&rft.date=1982&rft_id=info%3Adoi%2F10.1111%2Fj.1600-0498.1982.tb00667.x&rft_id=info%3Abibcode%2F1982Cent...26..317M&rft.aulast=Mel%27nikov&rft.aufirst=V.+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" 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="CITEREFBohr2008" class="citation book cs1">Bohr, Niels (June 2008). <a rel="nofollow" class="external text" href="https://archive.org/details/TheTheoryOfSpectraAndAtomicConstitution"><i>The Theory of Spectra and Atomic Constitution: Three Essays</i></a>. Kessinger. p. <a rel="nofollow" class="external text" href="https://archive.org/details/TheTheoryOfSpectraAndAtomicConstitution/page/n123">114</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4365-0368-6" title="Special:BookSources/978-1-4365-0368-6"><bdi>978-1-4365-0368-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Theory+of+Spectra+and+Atomic+Constitution%3A+Three+Essays&rft.pages=114&rft.pub=Kessinger&rft.date=2008-06&rft.isbn=978-1-4365-0368-6&rft.aulast=Bohr&rft.aufirst=Niels&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2FTheTheoryOfSpectraAndAtomicConstitution&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBury1921" class="citation journal cs1">Bury, Charles R. (1921). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1428812">"Langmuir's Theory of the Arrangement of Electrons in Atoms and Molecules"</a>. <i>J. Am. Chem. Soc</i>. <b>43</b> (7): 1602–1609. <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%2Fja01440a023">10.1021/ja01440a023</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=Langmuir%27s+Theory+of+the+Arrangement+of+Electrons+in+Atoms+and+Molecules&rft.volume=43&rft.issue=7&rft.pages=1602-1609&rft.date=1921&rft_id=info%3Adoi%2F10.1021%2Fja01440a023&rft.aulast=Bury&rft.aufirst=Charles+R.&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1428812&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaneth1922" class="citation book cs1 cs1-prop-foreign-lang-source">Paneth, F. 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(2005). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080528125634/http://wwwsoc.nii.ac.jp/jnrs/paper/JN62/jn6202.pdf">"Chemical studies on rutherfordium (Rf) at JAERI"</a> <span class="cs1-format">(PDF)</span>. <i>Radiochimica Acta</i>. <b>93</b> (9–10_2005): 519. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1524%2Fract.2005.93.9-10.519">10.1524/ract.2005.93.9-10.519</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:96299943">96299943</a>. Archived from <a rel="nofollow" class="external text" href="http://wwwsoc.nii.ac.jp/jnrs/paper/JN62/jn6202.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2008-05-28.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Radiochimica+Acta&rft.atitle=Chemical+studies+on+rutherfordium+%28Rf%29+at+JAERI&rft.volume=93&rft.issue=9%E2%80%9310_2005&rft.pages=519&rft.date=2005&rft_id=info%3Adoi%2F10.1524%2Fract.2005.93.9-10.519&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A96299943%23id-name%3DS2CID&rft.aulast=Nagame&rft.aufirst=Y.&rft.au=Tsukada%2C+K.&rft.au=Asai%2C+M.&rft.au=Toyoshima%2C+A.&rft.au=Akiyama%2C+K.&rft.au=Ishii%2C+Y.&rft.au=Kaneko-Sato%2C+T.&rft.au=Hirata%2C+M.&rft.au=Nishinaka%2C+I.&rft.au=Ichikawa%2C+S.&rft.au=Haba%2C+H.&rft.au=Enomoto%2C+Shuichi&rft_id=http%3A%2F%2Fwwwsoc.nii.ac.jp%2Fjnrs%2Fpaper%2FJN62%2Fjn6202.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-Greenwood958-28"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood958_28-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood958_28-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Greenwood958_28-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Greenwood958_28-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, pp. 958–61</span> </li> <li id="cite_note-Holl-29"><span class="mw-cite-backlink">^ <a href="#cite_ref-Holl_29-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Holl_29-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Holl_29-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHollemanWibergWiberg1985" class="citation book cs1 cs1-prop-foreign-lang-source">Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). <i>Lehrbuch der Anorganischen Chemie</i> (in German) (91–100 ed.). Walter de Gruyter. pp. 1056–1057. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/3-11-007511-3" title="Special:BookSources/3-11-007511-3"><bdi>3-11-007511-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Lehrbuch+der+Anorganischen+Chemie&rft.pages=1056-1057&rft.edition=91%E2%80%93100&rft.pub=Walter+de+Gruyter&rft.date=1985&rft.isbn=3-11-007511-3&rft.aulast=Holleman&rft.aufirst=Arnold+F.&rft.au=Wiberg%2C+Egon&rft.au=Wiberg%2C+Nils&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-primefan-30"><span class="mw-cite-backlink">^ <a href="#cite_ref-primefan_30-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-primefan_30-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.primefan.ru/stuff/chem/front2019.png">Periodic table poster</a> by A. V. Kulsha and T. A. Kolevich</span> </li> <li id="cite_note-Greenwood956-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood956_31-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 956–8</span> </li> <li id="cite_note-Greenwood946-32"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greenwood946_32-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greenwood946_32-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Greenwood and Earnshaw, pp. 946–8</span> </li> <li id="cite_note-hcp-33"><span class="mw-cite-backlink">^ <a href="#cite_ref-hcp_33-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-hcp_33-1"><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="CITEREFÖstlinVitos2011" class="citation journal cs1">Östlin, A.; Vitos, L. (2011). "First-principles calculation of the structural stability of 6d transition metals". <i>Physical Review B</i>. <b>84</b> (11): 113104. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2011PhRvB..84k3104O">2011PhRvB..84k3104O</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevB.84.113104">10.1103/PhysRevB.84.113104</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+B&rft.atitle=First-principles+calculation+of+the+structural+stability+of+6d+transition+metals&rft.volume=84&rft.issue=11&rft.pages=113104&rft.date=2011&rft_id=info%3Adoi%2F10.1103%2FPhysRevB.84.113104&rft_id=info%3Abibcode%2F2011PhRvB..84k3104O&rft.aulast=%C3%96stlin&rft.aufirst=A.&rft.au=Vitos%2C+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-Haire-34"><span class="mw-cite-backlink">^ <a href="#cite_ref-Haire_34-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Haire_34-1"><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="CITEREFHaire2006" class="citation book cs1">Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). 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New York: <a href="/wiki/Columbia_University_Press" title="Columbia University Press">Columbia University Press</a>. 2000–2006. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7876-5015-5" title="Special:BookSources/978-0-7876-5015-5"><bdi>978-0-7876-5015-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Titanium&rft.btitle=Columbia+Encyclopedia&rft.place=New+York&rft.edition=6th&rft.pub=Columbia+University+Press&rft.date=2000%2F2006&rft.isbn=978-0-7876-5015-5&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fcolumbiaencyclop00laga&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-EBC-36"><span class="mw-cite-backlink">^ <a href="#cite_ref-EBC_36-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-EBC_36-1"><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 class="citation encyclopaedia cs1"><a rel="nofollow" class="external text" href="http://www.britannica.com/eb/article-9072643/titanium">"Titanium"</a>. <i>Encyclopædia Britannica</i>. 2006<span class="reference-accessdate">. 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Retrieved <span class="nowrap">2023-09-23</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.rsc.org&rft.atitle=Zirconium+-+Element+information%2C+properties+and+uses+%7C+Periodic+Table&rft_id=https%3A%2F%2Fwww.rsc.org%2Fperiodic-table%2Felement%2F40%2Fzirconium%23%3A~%3Atext%3DZirconium%2520has%2520no%2520known%2520biological%2CIt%2520has%2520low%2520toxicity.%26text%3DZirconium%2520occurs%2520in%2520about%252030%2Cones%2520being%2520zircon%2520and%2520baddeleyite.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text">Karl Laden, 1999, Antiperspirants and Deodorants, CRC Press, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-8247-1746-5" title="Special:BookSources/0-8247-1746-5">0-8247-1746-5</a></span> </li> <li id="cite_note-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-60">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.rsc.org/periodic-table/element/72/hafnium#:~:text=Hafnium%20has%20no%20known%20biological%20role,%20and%20it%20has%20low%20toxicity.">"Hafnium - Element information, properties and uses | Periodic Table"</a>. <i>www.rsc.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-09-23</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.rsc.org&rft.atitle=Hafnium+-+Element+information%2C+properties+and+uses+%7C+Periodic+Table&rft_id=https%3A%2F%2Fwww.rsc.org%2Fperiodic-table%2Felement%2F72%2Fhafnium%23%3A~%3Atext%3DHafnium%2520has%2520no%2520known%2520biological%2520role%2C%2520and%2520it%2520has%2520low%2520toxicity.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-Emsley2001-61"><span class="mw-cite-backlink">^ <a href="#cite_ref-Emsley2001_61-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Emsley2001_61-1"><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="CITEREFEmsley2001" class="citation book cs1">Emsley, John (2001). "Titanium". <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/naturesbuildingb0000emsl"><i>Nature's Building Blocks: An A-Z Guide to the Elements</i></a></span>. Oxford, England, UK: Oxford University Press. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/naturesbuildingb0000emsl/page/457">457–458</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-850341-5" title="Special:BookSources/978-0-19-850341-5"><bdi>978-0-19-850341-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Titanium&rft.btitle=Nature%27s+Building+Blocks%3A+An+A-Z+Guide+to+the+Elements&rft.place=Oxford%2C+England%2C+UK&rft.pages=457-458&rft.pub=Oxford+University+Press&rft.date=2001&rft.isbn=978-0-19-850341-5&rft.aulast=Emsley&rft.aufirst=John&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fnaturesbuildingb0000emsl&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span><sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability"><span title="The material near this tag needs to be fact-checked with the cited source(s). (June 2020)">verification needed</span></a></i>]</sup></span> </li> <li id="cite_note-62"><span class="mw-cite-backlink"><b><a href="#cite_ref-62">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBerglundCarlmark,_Bjorn2011" class="citation journal cs1">Berglund, Fredrik; Carlmark, Bjorn (October 2011). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176400">"Titanium, Sinusitis, and the Yellow Nail Syndrome"</a>. <i>Biological Trace Element Research</i>. <b>143</b> (1): 1–7. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2011BTER..143....1B">2011BTER..143....1B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs12011-010-8828-5">10.1007/s12011-010-8828-5</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176400">3176400</a></span>. <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/20809268">20809268</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Biological+Trace+Element+Research&rft.atitle=Titanium%2C+Sinusitis%2C+and+the+Yellow+Nail+Syndrome&rft.volume=143&rft.issue=1&rft.pages=1-7&rft.date=2011-10&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3176400%23id-name%3DPMC&rft_id=info%3Apmid%2F20809268&rft_id=info%3Adoi%2F10.1007%2Fs12011-010-8828-5&rft_id=info%3Abibcode%2F2011BTER..143....1B&rft.aulast=Berglund&rft.aufirst=Fredrik&rft.au=Carlmark%2C+Bjorn&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3176400&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc14/icsc1405.htm">"Zirconium"</a>. <i>International Chemical Safety Card Database</i>. International Labour Organization. October 2004<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-03-30</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=International+Chemical+Safety+Card+Database&rft.atitle=Zirconium&rft.date=2004-10&rft_id=http%3A%2F%2Fwww.ilo.org%2Flegacy%2Fenglish%2Fprotection%2Fsafework%2Fcis%2Fproducts%2Ficsc%2Fdtasht%2F_icsc14%2Ficsc1405.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-64"><span class="mw-cite-backlink"><b><a href="#cite_ref-64">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cdc.gov/niosh/pel88/7440-67.html">"Zirconium Compounds"</a>. National Institute for Occupational Health and Safety. 2007-12-17<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-02-17</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Zirconium+Compounds&rft.pub=National+Institute+for+Occupational+Health+and+Safety&rft.date=2007-12-17&rft_id=https%3A%2F%2Fwww.cdc.gov%2Fniosh%2Fpel88%2F7440-67.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> <li id="cite_note-hafniumtox-65"><span class="mw-cite-backlink">^ <a href="#cite_ref-hafniumtox_65-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-hafniumtox_65-1"><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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20080313003040/https://www.osha.gov/SLTC/healthguidelines/hafnium/index.html">"Occupational Safety & Health Administration: Hafnium"</a>. U.S. Department of Labor. Archived from <a rel="nofollow" class="external text" href="https://www.osha.gov/SLTC/healthguidelines/hafnium/index.html">the original</a> on 2008-03-13<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-09-10</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Occupational+Safety+%26+Health+Administration%3A+Hafnium&rft.pub=U.S.+Department+of+Labor&rft_id=https%3A%2F%2Fwww.osha.gov%2FSLTC%2Fhealthguidelines%2Fhafnium%2Findex.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Bibliography">Bibliography</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Group_4_element&action=edit&section=15" title="Edit section: Bibliography"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreenwoodEarnshaw1997" class="citation book cs1"><a href="/wiki/Norman_Greenwood" title="Norman Greenwood">Greenwood, Norman N.</a>; Earnshaw, Alan (1997). <i>Chemistry of the Elements</i> (2nd ed.). <a href="/wiki/Butterworth-Heinemann" title="Butterworth-Heinemann">Butterworth-Heinemann</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-08-037941-8" title="Special:BookSources/978-0-08-037941-8"><bdi>978-0-08-037941-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemistry+of+the+Elements&rft.edition=2nd&rft.pub=Butterworth-Heinemann&rft.date=1997&rft.isbn=978-0-08-037941-8&rft.aulast=Greenwood&rft.aufirst=Norman+N.&rft.au=Earnshaw%2C+Alan&rfr_id=info%3Asid%2Fen.wikipedia.org%3AGroup+4+element" class="Z3988"></span></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist 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<tbody><tr> <td style="line-height:100%;"> </td> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Alkali_metal" title="Alkali metal">1</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Alkaline_earth_metal" title="Alkaline earth metal">2</a> </th> <td colspan="14"> </td> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_3_element" title="Group 3 element">3</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a class="mw-selflink selflink">4</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_5_element" title="Group 5 element">5</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_6_element" title="Group 6 element">6</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_7_element" title="Group 7 element">7</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_8_element" title="Group 8 element">8</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_9_element" title="Group 9 element">9</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_10_element" title="Group 10 element">10</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_11_element" title="Group 11 element">11</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Group_12_element" title="Group 12 element">12</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Boron_group" title="Boron group">13</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Carbon_group" title="Carbon group">14</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Pnictogen" title="Pnictogen">15</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Chalcogen" title="Chalcogen">16</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Halogen" title="Halogen">17</a> </th> <th scope="col" style="background:transparent; font-weight:normal;"><a href="/wiki/Noble_gas" title="Noble gas">18</a> </th></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_1_element" title="Period 1 element">1</a> </th> <td title="H, Hydrogen" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Hydrogen" title="Hydrogen"><span style="display:block">H</span></a></span> </td> <td colspan="30"> </td> <td title="He, Helium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Helium" title="Helium"><span style="display:block">He</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_2_element" title="Period 2 element">2</a> </th> <td title="Li, Lithium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Lithium" title="Lithium"><span style="display:block">Li</span></a></span> </td> <td title="Be, Beryllium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Beryllium" title="Beryllium"><span style="display:block">Be</span></a></span> </td> <td colspan="24"> </td> <td title="B, Boron" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Boron" title="Boron"><span style="display:block">B</span></a></span> </td> <td title="C, Carbon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Carbon" title="Carbon"><span style="display:block">C</span></a></span> </td> <td title="N, Nitrogen" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Nitrogen" title="Nitrogen"><span style="display:block">N</span></a></span> </td> <td title="O, Oxygen" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Oxygen" title="Oxygen"><span style="display:block">O</span></a></span> </td> <td title="F, Fluorine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Fluorine" title="Fluorine"><span style="display:block">F</span></a></span> </td> <td title="Ne, Neon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Neon" title="Neon"><span style="display:block">Ne</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_3_element" title="Period 3 element">3</a> </th> <td title="Na, Sodium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Sodium" title="Sodium"><span style="display:block">Na</span></a></span> </td> <td title="Mg, Magnesium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Magnesium" title="Magnesium"><span style="display:block">Mg</span></a></span> </td> <td colspan="24"> </td> <td title="Al, Aluminium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Aluminium" title="Aluminium"><span style="display:block">Al</span></a></span> </td> <td title="Si, Silicon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Silicon" title="Silicon"><span style="display:block">Si</span></a></span> </td> <td title="P, Phosphorus" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Phosphorus" title="Phosphorus"><span style="display:block">P</span></a></span> </td> <td title="S, Sulfur" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Sulfur" title="Sulfur"><span style="display:block">S</span></a></span> </td> <td title="Cl, Chlorine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Chlorine" title="Chlorine"><span style="display:block">Cl</span></a></span> </td> <td title="Ar, Argon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Argon" title="Argon"><span style="display:block">Ar</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_4_element" title="Period 4 element">4</a> </th> <td title="K, Potassium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Potassium" title="Potassium"><span style="display:block">K</span></a></span> </td> <td title="Ca, Calcium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Calcium" title="Calcium"><span style="display:block">Ca</span></a></span> </td> <td colspan="14"> </td> <td title="Sc, Scandium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Scandium" title="Scandium"><span style="display:block">Sc</span></a></span> </td> <td title="Ti, Titanium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Titanium" title="Titanium"><span style="display:block">Ti</span></a></span> </td> <td title="V, Vanadium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Vanadium" title="Vanadium"><span style="display:block">V</span></a></span> </td> <td title="Cr, Chromium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Chromium" title="Chromium"><span style="display:block">Cr</span></a></span> </td> <td title="Mn, Manganese" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Manganese" title="Manganese"><span style="display:block">Mn</span></a></span> </td> <td title="Fe, Iron" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Iron" title="Iron"><span style="display:block">Fe</span></a></span> </td> <td title="Co, Cobalt" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Cobalt" title="Cobalt"><span style="display:block">Co</span></a></span> </td> <td title="Ni, Nickel" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Nickel" title="Nickel"><span style="display:block">Ni</span></a></span> </td> <td title="Cu, Copper" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Copper" title="Copper"><span style="display:block">Cu</span></a></span> </td> <td title="Zn, Zinc" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Zinc" title="Zinc"><span style="display:block">Zn</span></a></span> </td> <td title="Ga, Gallium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Gallium" title="Gallium"><span style="display:block">Ga</span></a></span> </td> <td title="Ge, Germanium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Germanium" title="Germanium"><span style="display:block">Ge</span></a></span> </td> <td title="As, Arsenic" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Arsenic" title="Arsenic"><span style="display:block">As</span></a></span> </td> <td title="Se, Selenium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Selenium" title="Selenium"><span style="display:block">Se</span></a></span> </td> <td title="Br, Bromine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Bromine" title="Bromine"><span style="display:block">Br</span></a></span> </td> <td title="Kr, Krypton" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Krypton" title="Krypton"><span style="display:block">Kr</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_5_element" title="Period 5 element">5</a> </th> <td title="Rb, Rubidium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Rubidium" title="Rubidium"><span style="display:block">Rb</span></a></span> </td> <td title="Sr, Strontium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Strontium" title="Strontium"><span style="display:block">Sr</span></a></span> </td> <td colspan="14"> </td> <td title="Y, Yttrium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Yttrium" title="Yttrium"><span style="display:block">Y</span></a></span> </td> <td title="Zr, Zirconium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Zirconium" title="Zirconium"><span style="display:block">Zr</span></a></span> </td> <td title="Nb, Niobium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Niobium" title="Niobium"><span style="display:block">Nb</span></a></span> </td> <td title="Mo, Molybdenum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Molybdenum" title="Molybdenum"><span style="display:block">Mo</span></a></span> </td> <td title="Tc, Technetium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Technetium" title="Technetium"><span style="display:block">Tc</span></a></span> </td> <td title="Ru, Ruthenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Ruthenium" title="Ruthenium"><span style="display:block">Ru</span></a></span> </td> <td title="Rh, Rhodium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Rhodium" title="Rhodium"><span style="display:block">Rh</span></a></span> </td> <td title="Pd, Palladium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Palladium" title="Palladium"><span style="display:block">Pd</span></a></span> </td> <td title="Ag, Silver" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Silver" title="Silver"><span style="display:block">Ag</span></a></span> </td> <td title="Cd, Cadmium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Cadmium" title="Cadmium"><span style="display:block">Cd</span></a></span> </td> <td title="In, Indium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Indium" title="Indium"><span style="display:block">In</span></a></span> </td> <td title="Sn, Tin" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Tin" title="Tin"><span style="display:block">Sn</span></a></span> </td> <td title="Sb, Antimony" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Antimony" title="Antimony"><span style="display:block">Sb</span></a></span> </td> <td title="Te, Tellurium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Tellurium" title="Tellurium"><span style="display:block">Te</span></a></span> </td> <td title="I, Iodine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Iodine" title="Iodine"><span style="display:block">I</span></a></span> </td> <td title="Xe, Xenon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Xenon" title="Xenon"><span style="display:block">Xe</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_6_element" title="Period 6 element">6</a> </th> <td title="Cs, Caesium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Caesium" title="Caesium"><span style="display:block">Cs</span></a></span> </td> <td title="Ba, Barium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Barium" title="Barium"><span style="display:block">Ba</span></a></span> </td> <td title="La, Lanthanum" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Lanthanum" title="Lanthanum"><span style="display:block">La</span></a></span> </td> <td title="Ce, Cerium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Cerium" title="Cerium"><span style="display:block">Ce</span></a></span> </td> <td title="Pr, Praseodymium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Praseodymium" title="Praseodymium"><span style="display:block">Pr</span></a></span> </td> <td title="Nd, Neodymium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Neodymium" title="Neodymium"><span style="display:block">Nd</span></a></span> </td> <td title="Pm, Promethium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Promethium" title="Promethium"><span style="display:block">Pm</span></a></span> </td> <td title="Sm, Samarium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Samarium" title="Samarium"><span style="display:block">Sm</span></a></span> </td> <td title="Eu, Europium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Europium" title="Europium"><span style="display:block">Eu</span></a></span> </td> <td title="Gd, Gadolinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Gadolinium" title="Gadolinium"><span style="display:block">Gd</span></a></span> </td> <td title="Tb, Terbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Terbium" title="Terbium"><span style="display:block">Tb</span></a></span> </td> <td title="Dy, Dysprosium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Dysprosium" title="Dysprosium"><span style="display:block">Dy</span></a></span> </td> <td title="Ho, Holmium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Holmium" title="Holmium"><span style="display:block">Ho</span></a></span> </td> <td title="Er, Erbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Erbium" title="Erbium"><span style="display:block">Er</span></a></span> </td> <td title="Tm, Thulium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Thulium" title="Thulium"><span style="display:block">Tm</span></a></span> </td> <td title="Yb, Ytterbium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Ytterbium" title="Ytterbium"><span style="display:block">Yb</span></a></span> </td> <td title="Lu, Lutetium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Lutetium" title="Lutetium"><span style="display:block">Lu</span></a></span> </td> <td title="Hf, Hafnium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Hafnium" title="Hafnium"><span style="display:block">Hf</span></a></span> </td> <td title="Ta, Tantalum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Tantalum" title="Tantalum"><span style="display:block">Ta</span></a></span> </td> <td title="W, Tungsten" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Tungsten" title="Tungsten"><span style="display:block">W</span></a></span> </td> <td title="Re, Rhenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Rhenium" title="Rhenium"><span style="display:block">Re</span></a></span> </td> <td title="Os, Osmium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Osmium" title="Osmium"><span style="display:block">Os</span></a></span> </td> <td title="Ir, Iridium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Iridium" title="Iridium"><span style="display:block">Ir</span></a></span> </td> <td title="Pt, Platinum" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Platinum" title="Platinum"><span style="display:block">Pt</span></a></span> </td> <td title="Au, Gold" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Gold" title="Gold"><span style="display:block">Au</span></a></span> </td> <td title="Hg, Mercury" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Mercury_(element)" title="Mercury (element)"><span style="display:block">Hg</span></a></span> </td> <td title="Tl, Thallium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Thallium" title="Thallium"><span style="display:block">Tl</span></a></span> </td> <td title="Pb, Lead" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Lead" title="Lead"><span style="display:block">Pb</span></a></span> </td> <td title="Bi, Bismuth" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Bismuth" title="Bismuth"><span style="display:block">Bi</span></a></span> </td> <td title="Po, Polonium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Polonium" title="Polonium"><span style="display:block">Po</span></a></span> </td> <td title="At, Astatine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Astatine" title="Astatine"><span style="display:block">At</span></a></span> </td> <td title="Rn, Radon" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Radon" title="Radon"><span style="display:block">Rn</span></a></span> </td></tr> <tr> <th scope="row" style="background:transparent; font-weight:normal;"><a href="/wiki/Period_7_element" title="Period 7 element">7</a> </th> <td title="Fr, Francium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Francium" title="Francium"><span style="display:block">Fr</span></a></span> </td> <td title="Ra, Radium" style="text-align:center; background-color:#ff9999; border:none; ;"><span class="nowrap"><a href="/wiki/Radium" title="Radium"><span style="display:block">Ra</span></a></span> </td> <td title="Ac, Actinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Actinium" title="Actinium"><span style="display:block">Ac</span></a></span> </td> <td title="Th, Thorium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Thorium" title="Thorium"><span style="display:block">Th</span></a></span> </td> <td title="Pa, Protactinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Protactinium" title="Protactinium"><span style="display:block">Pa</span></a></span> </td> <td title="U, Uranium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Uranium" title="Uranium"><span style="display:block">U</span></a></span> </td> <td title="Np, Neptunium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Neptunium" title="Neptunium"><span style="display:block">Np</span></a></span> </td> <td title="Pu, Plutonium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Plutonium" title="Plutonium"><span style="display:block">Pu</span></a></span> </td> <td title="Am, Americium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Americium" title="Americium"><span style="display:block">Am</span></a></span> </td> <td title="Cm, Curium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Curium" title="Curium"><span style="display:block">Cm</span></a></span> </td> <td title="Bk, Berkelium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Berkelium" title="Berkelium"><span style="display:block">Bk</span></a></span> </td> <td title="Cf, Californium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Californium" title="Californium"><span style="display:block">Cf</span></a></span> </td> <td title="Es, Einsteinium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Einsteinium" title="Einsteinium"><span style="display:block">Es</span></a></span> </td> <td title="Fm, Fermium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Fermium" title="Fermium"><span style="display:block">Fm</span></a></span> </td> <td title="Md, Mendelevium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Mendelevium" title="Mendelevium"><span style="display:block">Md</span></a></span> </td> <td title="No, Nobelium" style="text-align:center; background-color:#9bff99; border:none; ;"><span class="nowrap"><a href="/wiki/Nobelium" title="Nobelium"><span style="display:block">No</span></a></span> </td> <td title="Lr, Lawrencium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Lawrencium" title="Lawrencium"><span style="display:block">Lr</span></a></span> </td> <td title="Rf, Rutherfordium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Rutherfordium" title="Rutherfordium"><span style="display:block">Rf</span></a></span> </td> <td title="Db, Dubnium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Dubnium" title="Dubnium"><span style="display:block">Db</span></a></span> </td> <td title="Sg, Seaborgium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Seaborgium" title="Seaborgium"><span style="display:block">Sg</span></a></span> </td> <td title="Bh, Bohrium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Bohrium" title="Bohrium"><span style="display:block">Bh</span></a></span> </td> <td title="Hs, Hassium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Hassium" title="Hassium"><span style="display:block">Hs</span></a></span> </td> <td title="Mt, Meitnerium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Meitnerium" title="Meitnerium"><span style="display:block">Mt</span></a></span> </td> <td title="Ds, Darmstadtium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Darmstadtium" title="Darmstadtium"><span style="display:block">Ds</span></a></span> </td> <td title="Rg, Roentgenium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Roentgenium" title="Roentgenium"><span style="display:block">Rg</span></a></span> </td> <td title="Cn, Copernicium" style="text-align:center; background-color:#99ccff; border:none; ;"><span class="nowrap"><a href="/wiki/Copernicium" title="Copernicium"><span style="display:block">Cn</span></a></span> </td> <td title="Nh, Nihonium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Nihonium" title="Nihonium"><span style="display:block">Nh</span></a></span> </td> <td title="Fl, Flerovium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Flerovium" title="Flerovium"><span style="display:block">Fl</span></a></span> </td> <td title="Mc, Moscovium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Moscovium" title="Moscovium"><span style="display:block">Mc</span></a></span> </td> <td title="Lv, Livermorium" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Livermorium" title="Livermorium"><span style="display:block">Lv</span></a></span> </td> <td title="Ts, Tennessine" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Tennessine" title="Tennessine"><span style="display:block">Ts</span></a></span> </td> <td title="Og, Oganesson" style="text-align:center; background-color:#fdff8c; border:none; ;"><span class="nowrap"><a href="/wiki/Oganesson" title="Oganesson"><span style="display:block">Og</span></a></span> </td></tr></tbody></table> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-even wraplinks" style="width:100%;padding:0"><div style="padding:0 0.25em"><div role="presentation" id="periodic-table-legend" style="border: 1px solid #a2a9b1; width:100%; line-height:120%; text-align:center; vertical-align:top; background:#f8f8f8; margin:0; margin:0;"><div style="padding:0.3em;"> <table style="width:100%; line-height:1.2em; table-layout:fixed; overflow:hidden; text-align:center;"> <tbody><tr> <td style="padding:0 1px; background:#ff9999;"><a href="/wiki/S-block" class="mw-redirect" title="S-block">s-block</a> </td> <td style="padding:0 1px; background:#9bff99;"><a href="/wiki/F-block" class="mw-redirect" title="F-block">f-block</a> </td> <td style="padding:0 1px; background:#99ccff;"><a href="/wiki/D-block" class="mw-redirect" title="D-block">d-block</a> </td> <td style="padding:0 1px; background:#fdff8c;"><a href="/wiki/P-block" class="mw-redirect" title="P-block">p-block</a> </td></tr></tbody></table> </div> </div></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Periodic_table" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Navbox_periodic_table" title="Template:Navbox periodic table"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Navbox_periodic_table" title="Template talk:Navbox periodic table"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Navbox_periodic_table" title="Special:EditPage/Template:Navbox periodic table"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Periodic_table" style="font-size:114%;margin:0 4em"><a href="/wiki/Periodic_table" title="Periodic table">Periodic table</a></div></th></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%;white-space: normal !important;">Periodic table forms</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Types_of_periodic_tables" title="Types of periodic tables">Alternatives</a></li> <li><a href="/wiki/Extended_periodic_table" title="Extended periodic table">Extended periodic table</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%;white-space: normal !important;"><a href="/wiki/Names_for_sets_of_chemical_elements" title="Names for sets of chemical elements">Sets of elements</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal !important;">By periodic table structure</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Group_(periodic_table)" title="Group (periodic table)">Groups</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Alkali_metal" title="Alkali metal">1 (Hydrogen and alkali metals)</a></li> <li><a href="/wiki/Alkaline_earth_metal" title="Alkaline earth metal">2 (Alkaline earth metals)</a></li> <li><a href="/wiki/Group_3_element" title="Group 3 element">3</a></li> <li><a class="mw-selflink selflink">4</a></li> <li><a href="/wiki/Group_5_element" title="Group 5 element">5</a></li> <li><a href="/wiki/Group_6_element" title="Group 6 element">6</a></li> <li><a href="/wiki/Group_7_element" title="Group 7 element">7</a></li> <li><a href="/wiki/Group_8_element" title="Group 8 element">8</a></li> <li><a href="/wiki/Group_9_element" title="Group 9 element">9</a></li> <li><a href="/wiki/Group_10_element" title="Group 10 element">10</a></li> <li><a href="/wiki/Group_11_element" title="Group 11 element">11</a></li> <li><a href="/wiki/Group_12_element" title="Group 12 element">12</a></li> <li><a href="/wiki/Boron_group" title="Boron group">13 (Triels)</a></li> <li><a href="/wiki/Carbon_group" title="Carbon group">14 (Tetrels)</a></li> <li><a href="/wiki/Pnictogen" title="Pnictogen">15 (Pnictogens)</a></li> <li><a href="/wiki/Chalcogen" title="Chalcogen">16 (Chalcogens)</a></li> <li><a href="/wiki/Halogen" title="Halogen">17 (Halogens)</a></li> <li><a href="/wiki/Noble_gas" title="Noble gas">18 (Noble gases)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Period_(periodic_table)" title="Period (periodic table)">Periods</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Period_1_element" title="Period 1 element">1</a></li> <li><a href="/wiki/Period_2_element" title="Period 2 element">2</a></li> <li><a href="/wiki/Period_3_element" title="Period 3 element">3</a></li> <li><a href="/wiki/Period_4_element" title="Period 4 element">4</a></li> <li><a href="/wiki/Period_5_element" title="Period 5 element">5</a></li> <li><a href="/wiki/Period_6_element" title="Period 6 element">6</a></li> <li><a href="/wiki/Period_7_element" title="Period 7 element">7</a></li> <li><a href="/wiki/Extended_periodic_table" title="Extended periodic table">8+</a> <ul><li><a href="/wiki/Extended_periodic_table#Aufbau_model" title="Extended periodic table">Aufbau</a></li> <li><a href="/wiki/Extended_periodic_table#Fricke" title="Extended periodic table">Fricke</a></li> <li><a href="/wiki/Extended_periodic_table#Pyykkö" title="Extended periodic table">Pyykkö</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Block_(periodic_table)" title="Block (periodic table)">Blocks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Aufbau_principle" title="Aufbau principle">Aufbau principle</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal !important;">By <a href="/wiki/Properties_of_metals,_metalloids_and_nonmetals" title="Properties of metals, metalloids and nonmetals">metallicity</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Metal" title="Metal">Metals</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Lanthanide" title="Lanthanide">Lanthanides</a></li> <li><a href="/wiki/Actinide" title="Actinide">Actinides</a></li> <li><a href="/wiki/Transition_metal" title="Transition metal">Transition metals</a></li> <li><a href="/wiki/Post-transition_metal" title="Post-transition metal">Post-transition metals</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Metalloid" title="Metalloid">Metalloids</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Lists_of_metalloids" title="Lists of metalloids">Lists of metalloids by source</a></li> <li><a href="/wiki/Dividing_line_between_metals_and_nonmetals" title="Dividing line between metals and nonmetals">Dividing line</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Nonmetal" title="Nonmetal">Nonmetals</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Noble_gas" title="Noble gas">Noble gases</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal !important;">Other sets</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Platinum_group" title="Platinum group">Platinum-group metals (PGM)</a></li> <li><a href="/wiki/Rare-earth_element" title="Rare-earth element">Rare-earth elements</a></li> <li><a href="/wiki/Refractory_metals" title="Refractory metals">Refractory metals</a></li> <li><a href="/wiki/Precious_metal" title="Precious metal">Precious metals</a></li> <li><a href="/wiki/Coinage_metals" title="Coinage metals">Coinage metals</a></li> <li><a href="/wiki/Noble_metal" title="Noble metal">Noble metals</a></li> <li><a href="/wiki/Heavy_metal_element" title="Heavy metal element">Heavy metals</a></li> <li><a href="/wiki/Native_metal" title="Native metal">Native metals</a></li> <li><a href="/wiki/Transuranium_element" title="Transuranium element">Transuranium elements</a></li> <li><a href="/wiki/Superheavy_element" title="Superheavy element">Superheavy elements</a></li> <li><a href="/wiki/Major_actinide" title="Major actinide">Major actinides</a></li> <li><a href="/wiki/Minor_actinide" title="Minor actinide">Minor actinides</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%;white-space: normal !important;"><a href="/wiki/Chemical_element" title="Chemical element">Elements</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal;"><a href="/wiki/List_of_chemical_elements" title="List of chemical elements">Lists</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>By: <a href="/wiki/Abundance_of_the_chemical_elements" title="Abundance of the chemical elements">Abundance</a> (<a href="/wiki/Composition_of_the_human_body" title="Composition of the human body">in humans</a>)</li> <li><a href="/wiki/List_of_elements_by_atomic_properties" title="List of elements by atomic properties">Atomic properties</a></li> <li><a href="/wiki/List_of_elements_by_stability_of_isotopes" title="List of elements by stability of isotopes">Nuclear stability</a></li> <li><a href="/wiki/Chemical_symbol" title="Chemical symbol">Symbol</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal;"><a href="/wiki/Chemical_element#Properties" title="Chemical element">Properties</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_aqueous_ions_by_element" title="List of aqueous ions by element">Aqueous chemistry</a></li> <li><a href="/wiki/Periodic_table_(crystal_structure)" title="Periodic table (crystal structure)">Crystal structure</a></li> <li><a href="/wiki/Periodic_table_(electron_configurations)" title="Periodic table (electron configurations)">Electron configuration</a></li> <li><a href="/wiki/Electronegativity" title="Electronegativity">Electronegativity</a></li> <li><a href="/wiki/Goldschmidt_classification" title="Goldschmidt classification">Goldschmidt classification</a></li> <li><a href="/wiki/Term_symbol" title="Term symbol">Term symbol</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;white-space: normal;">Data pages</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Abundances_of_the_elements_(data_page)" title="Abundances of the elements (data page)">Abundance</a></li> <li><a href="/wiki/Atomic_radii_of_the_elements_(data_page)" title="Atomic radii of the elements (data page)">Atomic radius</a></li> <li><a href="/wiki/Boiling_points_of_the_elements_(data_page)" title="Boiling points of the elements (data page)">Boiling point</a></li> <li><a href="/wiki/Critical_points_of_the_elements_(data_page)" title="Critical points of the elements (data page)">Critical point</a></li> <li><a href="/wiki/Densities_of_the_elements_(data_page)" title="Densities of the elements (data page)">Density</a></li> <li><a href="/wiki/Elastic_properties_of_the_elements_(data_page)" title="Elastic properties of the elements (data page)">Elasticity</a></li> <li><a href="/wiki/Electrical_resistivities_of_the_elements_(data_page)" title="Electrical resistivities of the elements (data page)">Electrical resistivity</a></li> <li><a href="/wiki/Electron_affinity_(data_page)" title="Electron affinity (data page)">Electron affinity</a></li> <li><a href="/wiki/Electron_configurations_of_the_elements_(data_page)" title="Electron configurations of the elements (data page)">Electron configuration</a></li> <li><a href="/wiki/Electronegativities_of_the_elements_(data_page)" title="Electronegativities of the elements (data page)">Electronegativity</a></li> <li><a href="/wiki/Hardnesses_of_the_elements_(data_page)" title="Hardnesses of the elements (data page)">Hardness</a></li> <li><a href="/wiki/Heat_capacities_of_the_elements_(data_page)" title="Heat capacities of the elements (data page)">Heat capacity</a></li> <li><a href="/wiki/Heats_of_fusion_of_the_elements_(data_page)" title="Heats of fusion of the elements (data page)">Heat of fusion</a></li> <li><a href="/wiki/Heats_of_vaporization_of_the_elements_(data_page)" title="Heats of vaporization of the elements (data page)">Heat of vaporization</a></li> <li><a href="/wiki/Ionization_energies_of_the_elements_(data_page)" title="Ionization energies of the elements (data page)">Ionization energy</a></li> <li><a href="/wiki/Melting_points_of_the_elements_(data_page)" title="Melting points of the elements (data page)">Melting point</a></li> <li><a href="/wiki/Oxidation_state" title="Oxidation state">Oxidation state</a></li> <li><a href="/wiki/Speeds_of_sound_of_the_elements" title="Speeds of sound of the elements">Speed of sound</a></li> <li><a href="/wiki/Thermal_conductivities_of_the_elements_(data_page)" title="Thermal conductivities of the elements (data page)">Thermal conductivity</a></li> <li><a href="/wiki/Thermal_expansivities_of_the_elements" title="Thermal expansivities of the elements">Thermal expansion coefficient</a></li> <li><a href="/wiki/Vapor_pressures_of_the_elements_(data_page)" title="Vapor pressures of the elements (data page)">Vapor pressure</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%;white-space: normal !important;"><a href="/wiki/History_of_the_periodic_table" title="History of the periodic table">History</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Discovery_of_chemical_elements" title="Discovery of chemical elements">Element discoveries</a> <ul><li><a href="/wiki/Dmitri_Mendeleev" title="Dmitri Mendeleev">Dmitri Mendeleev</a></li> <li><a href="/wiki/Dmitri_Mendeleev#Periodic_table" title="Dmitri Mendeleev">1871 table</a></li> <li><a href="/wiki/Mendeleev%27s_predicted_elements" title="Mendeleev's predicted elements">1869 predictions</a></li></ul></li> <li><a href="/wiki/Naming_of_chemical_elements" title="Naming of chemical elements">Naming</a> <ul><li><a href="/wiki/List_of_chemical_element_name_etymologies" title="List of chemical element name etymologies">etymology</a></li> <li><a href="/wiki/List_of_chemical_element_naming_controversies" title="List of chemical element naming controversies">controversies</a></li> <li><a href="/wiki/List_of_chemical_elements_named_after_places" title="List of chemical elements named after places">for places</a></li> <li><a href="/wiki/List_of_chemical_elements_named_after_people" title="List of chemical elements named after people">for people</a></li> <li><a href="/wiki/Chemical_elements_in_East_Asian_languages" title="Chemical elements in East Asian languages">in East Asian languages</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%;white-space: normal !important;">See also</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/International_Union_of_Pure_and_Applied_Chemistry" title="International Union of Pure and Applied Chemistry">IUPAC</a> <ul><li><a href="/wiki/Chemical_nomenclature" title="Chemical nomenclature">nomenclature</a></li> <li><a href="/wiki/Systematic_element_name" title="Systematic element name">systematic element name</a></li></ul></li> <li><a href="/wiki/Trivial_name" title="Trivial name">Trivial name</a></li> <li><a href="/wiki/Dmitri_Mendeleev" title="Dmitri Mendeleev">Dmitri Mendeleev</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><b><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Periodic_table" title="Category:Periodic table">Category</a></b></li> <li><b><span class="noviewer" typeof="mw:File"><span title="WikiProject"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/16px-People_icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/24px-People_icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/32px-People_icon.svg.png 2x" data-file-width="100" data-file-height="100" /></span></span> <a href="/wiki/Wikipedia:WikiProject_Elements" title="Wikipedia:WikiProject Elements">WikiProject</a></b></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Group_4_elements" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Group_4_elements" title="Template:Group 4 elements"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Group_4_elements" title="Template talk:Group 4 elements"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Group_4_elements" title="Special:EditPage/Template:Group 4 elements"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Group_4_elements" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Group 4 elements</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0;background:transparent;color:inherit;"><div style="padding:0px"><table class="navbox-columns-table" style="border-spacing: 0px; text-align:left;width:auto; margin-left:auto; margin-right:auto;"><tbody><tr style="vertical-align:top"><td style="width:5em;">   </td><td class="navbox-list" style="padding:0px;text-align:center;width:25%;"><div> <p><a href="/wiki/Titanium" title="Titanium">Titanium</a> <br /> <b>Ti</b> <br /> <small>Atomic Number: 22 <br /> Atomic Weight: 47.867 <br /> Melting Point: 1933.15 K<br />Boiling Point: 3560 K<br />Specific mass: 4.54 g/cm<sup>3</sup><br /> Electronegativity: 1.54</small> </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:25%;"><div> <p><a href="/wiki/Zirconium" title="Zirconium">Zirconium</a> <br /> <b>Zr</b> <br /> <small>Atomic Number: 40 <br /> Atomic Weight: 91.224 <br /> Melting Point: 2125.15 K<br /> Boiling Point: 4682 K<br />Specific mass: 6.506 g/cm<sup>3</sup><br /> Electronegativity: 1.33</small> </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:25%;"><div> <p><a href="/wiki/Hafnium" title="Hafnium">Hafnium</a> <br /> <b>Hf</b> <br /> <small>Atomic Number: 72 <br /> Atomic Weight: 178.49 <br /> Melting Point: 2500.15 K<br /> Boiling Point: 4876 K<br />Specific mass: 13.31 g/cm<sup>3</sup><br /> Electronegativity: 1.3</small> </p> </div></td><td class="navbox-list" style="border-left:2px solid #fdfdfd;padding:0px;text-align:center;width:25%;"><div> <p><a href="/wiki/Rutherfordium" title="Rutherfordium">Rutherfordium</a> <br /> <b>Rf</b> <br /> <small>Atomic Number: 104 <br /> Atomic Weight: [267] <br /> Melting Point: ? 2400 K<br /> Boiling Point: ? 5800 K<br />Specific mass: ? 23 g/cm<sup>3</sup><br /> Electronegativity: ?</small> </p> </div></td></tr></tbody></table></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output .tooltip-dotted{border-bottom:1px dotted;cursor:help}</style></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" 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