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class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Funci%C3%B3_d%27acidesa" title="Funció d'acidesa – Catalan" lang="ca" hreflang="ca" data-title="Funció d'acidesa" 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/Hammettova_kyselostn%C3%AD_funkce" title="Hammettova kyselostní funkce – Czech" lang="cs" hreflang="cs" data-title="Hammettova kyselostní funkce" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Hammettsche_Acidit%C3%A4tsfunktion" title="Hammettsche Aciditätsfunktion – German" lang="de" hreflang="de" data-title="Hammettsche Aciditätsfunktion" 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/Funci%C3%B3n_de_acidez_de_Hammett" title="Función de acidez de Hammett – Spanish" lang="es" hreflang="es" data-title="Función de acidez de Hammett" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AA%D8%A7%D8%A8%D8%B9_%D8%A7%D8%B3%DB%8C%D8%AF%DB%8C_%D9%87%D8%A7%D9%85%D8%AA" title="تابع اسیدی هامت – Persian" lang="fa" hreflang="fa" data-title="تابع اسیدی هامت" 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/%C3%89chelle_de_Hammett" title="Échelle de Hammett – French" lang="fr" hreflang="fr" data-title="Échelle de Hammett" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Fungsi_keasaman_Hammett" title="Fungsi keasaman Hammett – Indonesian" lang="id" hreflang="id" data-title="Fungsi keasaman Hammett" 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/Funzione_di_acidit%C3%A0_di_Hammett" title="Funzione di acidità di Hammett – Italian" lang="it" hreflang="it" data-title="Funzione di acidità di Hammett" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Hammett-zuurfunctie" title="Hammett-zuurfunctie – Dutch" lang="nl" hreflang="nl" data-title="Hammett-zuurfunctie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Funkcja_kwasowo%C5%9Bci_Hammetta" title="Funkcja kwasowości Hammetta – Polish" lang="pl" hreflang="pl" data-title="Funkcja kwasowości Hammetta" 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/Fun%C3%A7%C3%A3o_acidez_de_Hammett" title="Função acidez de Hammett – Portuguese" lang="pt" hreflang="pt" data-title="Função acidez de Hammett" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A4%D1%83%D0%BD%D0%BA%D1%86%D0%B8%D1%8F_%D0%BA%D0%B8%D1%81%D0%BB%D0%BE%D1%82%D0%BD%D0%BE%D1%81%D1%82%D0%B8_%D0%93%D0%B0%D0%BC%D0%BC%D0%B5%D1%82%D0%B0" title="Функция кислотности Гаммета – Russian" lang="ru" hreflang="ru" data-title="Функция кислотности Гаммета" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Fungsi_kaasaman_Hammett" title="Fungsi kaasaman Hammett – Sundanese" lang="su" hreflang="su" data-title="Fungsi kaasaman Hammett" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a 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<div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Measure of acidity for very strong acids</div> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" 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.sidebar{width:22em;float:right;clear:right;margin:0.5em 0 1em 1em;background:var(--background-color-neutral-subtle,#f8f9fa);border:1px solid var(--border-color-base,#a2a9b1);padding:0.2em;text-align:center;line-height:1.4em;font-size:88%;border-collapse:collapse;display:table}body.skin-minerva .mw-parser-output .sidebar{display:table!important;float:right!important;margin:0.5em 0 1em 1em!important}.mw-parser-output .sidebar-subgroup{width:100%;margin:0;border-spacing:0}.mw-parser-output .sidebar-left{float:left;clear:left;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-none{float:none;clear:both;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-outer-title{padding:0 0.4em 0.2em;font-size:125%;line-height:1.2em;font-weight:bold}.mw-parser-output .sidebar-top-image{padding:0.4em}.mw-parser-output .sidebar-top-caption,.mw-parser-output .sidebar-pretitle-with-top-image,.mw-parser-output .sidebar-caption{padding:0.2em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-pretitle{padding:0.4em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-title,.mw-parser-output .sidebar-title-with-pretitle{padding:0.2em 0.8em;font-size:145%;line-height:1.2em}.mw-parser-output .sidebar-title-with-pretitle{padding:0.1em 0.4em}.mw-parser-output .sidebar-image{padding:0.2em 0.4em 0.4em}.mw-parser-output .sidebar-heading{padding:0.1em 0.4em}.mw-parser-output .sidebar-content{padding:0 0.5em 0.4em}.mw-parser-output .sidebar-content-with-subgroup{padding:0.1em 0.4em 0.2em}.mw-parser-output .sidebar-above,.mw-parser-output .sidebar-below{padding:0.3em 0.8em;font-weight:bold}.mw-parser-output .sidebar-collapse .sidebar-above,.mw-parser-output .sidebar-collapse .sidebar-below{border-top:1px solid #aaa;border-bottom:1px solid #aaa}.mw-parser-output .sidebar-navbar{text-align:right;font-size:115%;padding:0 0.4em 0.4em}.mw-parser-output .sidebar-list-title{padding:0 0.4em;text-align:left;font-weight:bold;line-height:1.6em;font-size:105%}.mw-parser-output .sidebar-list-title-c{padding:0 0.4em;text-align:center;margin:0 3.3em}@media(max-width:640px){body.mediawiki .mw-parser-output .sidebar{width:100%!important;clear:both;float:none!important;margin-left:0!important;margin-right:0!important}}body.skin--responsive .mw-parser-output .sidebar a>img{max-width:none!important}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><table class="sidebar nomobile nowraplinks"><tbody><tr><th class="sidebar-title" style="background:#d3d3d3;">Acids and bases</th></tr><tr><td class="sidebar-image"><span typeof="mw:File"><a href="/wiki/File:Acetic-acid-dissociation-3D-balls.png" class="mw-file-description" title="Diagrammatic representation of the dissociation of acetic acid in aqueous solution to acetate and hydronium ions."><img alt="Diagrammatic representation of the dissociation of acetic acid in aqueous solution to acetate and hydronium ions." src="//upload.wikimedia.org/wikipedia/commons/thumb/9/96/Acetic-acid-dissociation-3D-balls.png/220px-Acetic-acid-dissociation-3D-balls.png" decoding="async" width="220" height="52" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/96/Acetic-acid-dissociation-3D-balls.png/330px-Acetic-acid-dissociation-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/96/Acetic-acid-dissociation-3D-balls.png/440px-Acetic-acid-dissociation-3D-balls.png 2x" data-file-width="2150" data-file-height="513" /></a></span></td></tr><tr><td class="sidebar-content hlist" style="padding:0.2em 0 0.75em;"> <ul><li><a href="/wiki/Acceptor_number" class="mw-redirect" title="Acceptor number">Acceptor number</a></li> <li><a href="/wiki/Acid" title="Acid">Acid</a></li> <li><a href="/wiki/Acid%E2%80%93base_reaction" title="Acid–base reaction">Acid–base reaction</a></li> <li><a href="/wiki/Acid%E2%80%93base_homeostasis" title="Acid–base homeostasis">Acid–base homeostasis</a></li> <li><a href="/wiki/Acid_strength" title="Acid strength">Acid strength</a></li> <li><a href="/wiki/Acidity_function" title="Acidity function">Acidity function</a></li> <li><a href="/wiki/Amphoterism" title="Amphoterism">Amphoterism</a></li> <li><a href="/wiki/Base_(chemistry)" title="Base (chemistry)">Base</a></li> <li><a href="/wiki/Buffer_solution" title="Buffer solution">Buffer solutions</a></li> <li><a href="/wiki/Dissociation_constant" title="Dissociation constant">Dissociation constant</a></li> <li><a href="/wiki/Donor_number" title="Donor number">Donor number</a></li> <li><a href="/wiki/Equilibrium_chemistry" title="Equilibrium chemistry">Equilibrium chemistry</a></li> <li><a href="/wiki/Acid%E2%80%93base_extraction" title="Acid–base extraction">Extraction</a></li> <li><a class="mw-selflink selflink">Hammett acidity function</a></li> <li><a href="/wiki/PH" title="PH">pH</a></li> <li><a href="/wiki/Proton_affinity" title="Proton affinity">Proton affinity</a></li> <li><a href="/wiki/Self-ionization_of_water" title="Self-ionization of water">Self-ionization of water</a></li> <li><a href="/wiki/Acid%E2%80%93base_titration" title="Acid–base titration">Titration</a></li> <li><a href="/wiki/Lewis_acid_catalysis" title="Lewis acid catalysis">Lewis acid catalysis</a></li> <li><a href="/wiki/Frustrated_Lewis_pair" title="Frustrated Lewis pair">Frustrated Lewis pair</a></li> <li><a href="/wiki/Chiral_Lewis_acid" title="Chiral Lewis acid">Chiral Lewis acid</a></li> <li><a href="/wiki/ECW_model" title="ECW model">ECW model</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#e5e5e5;"> <a href="/wiki/Acid" title="Acid">Acid</a> types</th></tr><tr><td class="sidebar-content hlist" style="padding:0.2em 0 0.75em;"> <ul><li><a href="/wiki/Br%C3%B8nsted%E2%80%93Lowry_acid%E2%80%93base_theory" title="Brønsted–Lowry acid–base theory">Brønsted–Lowry</a></li> <li><a href="/wiki/Lewis_acids_and_bases" title="Lewis acids and bases">Lewis</a></li> <li><a href="/wiki/Mineral_acid" title="Mineral acid">Mineral</a></li> <li><a href="/wiki/Organic_acid" title="Organic acid">Organic</a></li> <li><a href="/wiki/Acidic_oxide" title="Acidic oxide">Oxide</a></li> <li><a href="/wiki/Strong_acid" class="mw-redirect" title="Strong acid">Strong</a></li> <li><a href="/wiki/Superacid" title="Superacid">Superacids</a></li> <li><a href="/wiki/Weak_acid" class="mw-redirect" title="Weak acid">Weak</a></li> <li><a href="/wiki/Solid_acid" title="Solid acid">Solid</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#e5e5e5;"> <a href="/wiki/Base_(chemistry)" title="Base (chemistry)">Base</a> types</th></tr><tr><td class="sidebar-content hlist" style="padding:0.2em 0 0.75em;"> <ul><li><a href="/wiki/Br%C3%B8nsted%E2%80%93Lowry_acid%E2%80%93base_theory" title="Brønsted–Lowry acid–base theory">Brønsted–Lowry</a></li> <li><a href="/wiki/Lewis_acids_and_bases" title="Lewis acids and bases">Lewis</a></li> <li><a href="/wiki/Organic_base" title="Organic base">Organic</a></li> <li><a href="/wiki/Basic_oxide" title="Basic oxide">Oxide</a></li> <li><a href="/wiki/Base_(chemistry)#Strong_bases" title="Base (chemistry)">Strong</a></li> <li><a href="/wiki/Superbase" title="Superbase">Superbases</a></li> <li><a href="/wiki/Non-nucleophilic_base" title="Non-nucleophilic base">Non-nucleophilic</a></li> <li><a href="/wiki/Weak_base" title="Weak base">Weak</a></li></ul></td> </tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Acids_and_bases" title="Template:Acids and bases"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Acids_and_bases" title="Template talk:Acids and bases"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Acids_and_bases" title="Special:EditPage/Template:Acids and bases"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p>The <b>Hammett acidity function</b> (<i>H</i><sub>0</sub>) is a measure of acidity that is used for very concentrated solutions of strong <a href="/wiki/Acid" title="Acid">acids</a>, including <a href="/wiki/Superacid" title="Superacid">superacids</a>. It was proposed by the physical organic chemist <a href="/wiki/Louis_Plack_Hammett" title="Louis Plack Hammett">Louis Plack Hammett</a><sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> and is the best-known <a href="/wiki/Acidity_function" title="Acidity function">acidity function</a> used to extend the measure of <a href="/wiki/Br%C3%B8nsted%E2%80%93Lowry_acid%E2%80%93base_theory" title="Brønsted–Lowry acid–base theory">Brønsted–Lowry</a> acidity beyond the dilute <a href="/wiki/Aqueous_solutions" class="mw-redirect" title="Aqueous solutions">aqueous solutions</a> for which the <a href="/wiki/PH" title="PH">pH</a> scale is useful. </p><p>In highly concentrated solutions, simple approximations such as the <a href="/wiki/Henderson%E2%80%93Hasselbalch_equation" title="Henderson–Hasselbalch equation">Henderson–Hasselbalch equation</a> are no longer valid due to the variations of the <a href="/wiki/Activity_coefficient" title="Activity coefficient">activity coefficients</a>. The Hammett acidity function is used in fields such as <a href="/wiki/Physical_organic_chemistry" title="Physical organic chemistry">physical organic chemistry</a> for the study of <a href="/wiki/Acid-catalyzed" class="mw-redirect" title="Acid-catalyzed">acid-catalyzed</a> reactions, because some of these reactions use acids in very high concentrations, or even neat (pure).<sup id="cite_ref-poc_3-0" class="reference"><a href="#cite_note-poc-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Definition">Definition</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hammett_acidity_function&action=edit&section=1" title="Edit section: Definition"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The Hammett acidity function, <i>H</i><sub>0</sub>, can replace the <a href="/wiki/PH" title="PH">pH</a> in concentrated solutions. It is defined using an equation<sup id="cite_ref-Jolly_4-0" class="reference"><a href="#cite_note-Jolly-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> analogous to the Henderson–Hasselbalch equation: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle H_{0}={\mbox{p}}K_{{\ce {BH^+}}}+\log {\frac {{\ce {[B]}}}{{\ce {[BH^+]}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>H</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mtext>p</mtext> </mstyle> </mrow> <msub> <mi>K</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <msup> <mtext>BH</mtext> <mrow class="MJX-TeXAtom-ORD"> <mo>+</mo> </mrow> </msup> </mrow> </mrow> </msub> <mo>+</mo> <mi>log</mi> <mo>⁡</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">[</mo> <mtext>B</mtext> <mo stretchy="false">]</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">[</mo> <msup> <mtext>BH</mtext> <mrow class="MJX-TeXAtom-ORD"> <mo>+</mo> </mrow> </msup> <mo stretchy="false">]</mo> </mrow> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle H_{0}={\mbox{p}}K_{{\ce {BH^+}}}+\log {\frac {{\ce {[B]}}}{{\ce {[BH^+]}}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/676b064ea9333d0e387ce376b541250baf004079" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.838ex; width:26.409ex; height:6.676ex;" alt="{\displaystyle H_{0}={\mbox{p}}K_{{\ce {BH^+}}}+\log {\frac {{\ce {[B]}}}{{\ce {[BH^+]}}}}}"></span></dd></dl> <p>where log(x) is the <a href="/wiki/Common_logarithm" title="Common logarithm">common logarithm</a> of x, and p<i>K</i><sub>BH<sup>+</sup></sub> is −log(<i>K</i>) for the dissociation of BH<sup>+</sup>, which is the <a href="/wiki/Conjugate_acid" class="mw-redirect" title="Conjugate acid">conjugate acid</a> of a very weak base B, with a very negative p<i>K</i><sub>BH<sup>+</sup></sub>. In this way, it is rather as if the pH scale has been extended to very negative values. Hammett originally used a series of <a href="/wiki/Aniline" title="Aniline">anilines</a> with <a href="/wiki/Electron-withdrawing_group" title="Electron-withdrawing group">electron-withdrawing groups</a> for the bases.<sup id="cite_ref-poc_3-1" class="reference"><a href="#cite_note-poc-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>Hammett also pointed out the equivalent form </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle H_{0}=-\log \left(a_{{\ce {H^+}}}{\frac {\gamma _{{\ce {B}}}}{\gamma _{{\ce {BH^+}}}}}\right)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>H</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mi>log</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mrow> <msub> <mi>a</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <msup> <mtext>H</mtext> <mrow class="MJX-TeXAtom-ORD"> <mo>+</mo> </mrow> </msup> </mrow> </mrow> </msub> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msub> <mi>γ</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mtext>B</mtext> </mrow> </mrow> </msub> <msub> <mi>γ</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <msup> <mtext>BH</mtext> <mrow class="MJX-TeXAtom-ORD"> <mo>+</mo> </mrow> </msup> </mrow> </mrow> </msub> </mfrac> </mrow> </mrow> <mo>)</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle H_{0}=-\log \left(a_{{\ce {H^+}}}{\frac {\gamma _{{\ce {B}}}}{\gamma _{{\ce {BH^+}}}}}\right)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5a949880e982e11404e412bc50d669873426b056" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:24.44ex; height:6.176ex;" alt="{\displaystyle H_{0}=-\log \left(a_{{\ce {H^+}}}{\frac {\gamma _{{\ce {B}}}}{\gamma _{{\ce {BH^+}}}}}\right)}"></span></dd></dl> <p>where <span class="texhtml mvar" style="font-style:italic;">a</span> is the activity, and the <i>γ</i> are thermodynamic <a href="/wiki/Activity_coefficients" class="mw-redirect" title="Activity coefficients">activity coefficients</a>. In dilute aqueous solution (pH 0–14) the predominant acid species is H<sub>3</sub>O<sup>+</sup> and the activity coefficients are close to unity, so <i>H</i><sub>0</sub> is approximately equal to the pH. However, beyond this pH range, the effective hydrogen-ion activity changes much more rapidly than the concentration.<sup id="cite_ref-Jolly_4-1" class="reference"><a href="#cite_note-Jolly-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> This is often due to changes in the nature of the acid species; for example in concentrated <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a>, the predominant acid species ("H<sup>+</sup>") is not H<sub>3</sub>O<sup>+</sup> but rather H<sub>3</sub>SO<sub>4</sub><sup>+</sup><sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (January 2020)">citation needed</span></a></i>]</sup>, which is a much stronger acid. The value <i>H</i><sub>0</sub> = -12 for pure sulfuric acid must not be interpreted as pH = −12 (which would imply an impossibly high H<sub>3</sub>O<sup>+</sup> concentration of 10<sup>+12</sup> mol/L in <a href="/wiki/Ideal_solution" title="Ideal solution">ideal solution</a>). Instead it means that the acid species present (H<sub>3</sub>SO<sub>4</sub><sup>+</sup>) has a <a href="/wiki/Protonating" class="mw-redirect" title="Protonating">protonating</a> ability equivalent to H<sub>3</sub>O<sup>+</sup> at a fictitious (ideal) concentration of 10<sup>12</sup> mol/L, as measured by its ability to protonate weak bases. </p><p>Although the Hammett acidity function is the best known <a href="/wiki/Acidity_function" title="Acidity function">acidity function</a>, other acidity functions have been developed by authors such as Arnett, Cox, Katrizky, Yates, and Stevens.<sup id="cite_ref-poc_3-2" class="reference"><a href="#cite_note-poc-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Typical_values">Typical values</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Hammett_acidity_function&action=edit&section=2" title="Edit section: Typical values"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>On this scale, pure <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">H<sub>2</sub>SO<sub>4</sub></a> (18.4 <a href="/wiki/Concentration#Molarity" title="Concentration">M</a>) has a <i>H</i><sub>0</sub> value of −12, and <a href="/wiki/Pyrosulfuric_acid" class="mw-redirect" title="Pyrosulfuric acid">pyrosulfuric acid</a> has <i>H</i><sub>0</sub> ~ −15.<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> Take note that the Hammett acidity function clearly avoids water in its equation. It is a generalization of the pH scale—in a dilute aqueous solution (where B is H<sub>2</sub>O), pH is very nearly equal to <i>H</i><sub>0</sub>. By using a solvent-independent quantitative measure of acidity, the implications of the <a href="/wiki/Leveling_effect" title="Leveling effect">leveling effect</a> are eliminated, and it becomes possible to directly compare the acidities of different substances (e.g. using p<i>K</i><sub>a</sub>, HF is weaker than HCl or H<sub>2</sub>SO<sub>4</sub> in water but stronger than HCl in glacial acetic acid.<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><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>) </p> <table class="wikitable sortable"> <caption>List of acids by Hammett acidity </caption> <tbody><tr> <th>Name </th> <th>H<sub>0</sub> </th> <th>Ref </th></tr> <tr> <td><a href="/wiki/Trifluoroacetic_acid" title="Trifluoroacetic acid">Trifluoroacetic acid</a> </td> <td>-2.7 </td> <td><sup id="cite_ref-b_10-0" class="reference"><a href="#cite_note-b-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Phosphoric_acid" title="Phosphoric acid">Phosphoric acid</a> </td> <td>-4.66 </td> <td><sup id="cite_ref-d_11-0" class="reference"><a href="#cite_note-d-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Nitric_acid" title="Nitric acid">Nitric acid</a> </td> <td>-6.3 </td> <td><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> </td></tr> <tr> <td><a href="/wiki/Methanesulfonic_acid" title="Methanesulfonic acid">Methanesulfonic acid</a> </td> <td>-7.86 </td> <td><sup id="cite_ref-d_11-1" class="reference"><a href="#cite_note-d-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Sulfuric_acid" title="Sulfuric acid">Sulfuric acid</a> </td> <td>-11.93 </td> <td><sup id="cite_ref-a_13-0" class="reference"><a href="#cite_note-a-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Perchloric_acid" title="Perchloric acid">Perchloric acid</a> </td> <td>-13 </td> <td><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> </td></tr> <tr> <td><a href="/wiki/Triflic_acid" title="Triflic acid">Triflic acid</a> </td> <td>-13.7 </td> <td><sup id="cite_ref-b_10-1" class="reference"><a href="#cite_note-b-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Chlorosulfuric_acid" title="Chlorosulfuric acid">Chlorosulfuric acid</a> </td> <td>-13.79 </td> <td><sup id="cite_ref-a_13-1" class="reference"><a href="#cite_note-a-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Oleum" title="Oleum">Oleum</a> (50 mole% SO<sub>3</sub>) </td> <td>-14.44 </td> <td><sup id="cite_ref-a_13-2" class="reference"><a href="#cite_note-a-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Fluorosulfuric_acid" title="Fluorosulfuric acid">Fluorosulfuric acid</a> </td> <td>-15.07 </td> <td><sup id="cite_ref-a_13-3" class="reference"><a href="#cite_note-a-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Hydrogen_fluoride" title="Hydrogen fluoride">Hydrogen fluoride</a> </td> <td>-15.1 </td> <td><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> </td></tr> <tr> <td><a href="/wiki/Magic_acid" title="Magic acid">Magic acid</a> (1:1 FSO<sub>3</sub>H-SbF<sub>5</sub>) </td> <td>-23.0 </td> <td><sup id="cite_ref-e_16-0" class="reference"><a href="#cite_note-e-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Fluoroantimonic_acid" title="Fluoroantimonic acid">Fluoroantimonic acid</a> (1:1 HF-SbF<sub>5</sub>) </td> <td>-28 </td> <td><sup id="cite_ref-e_16-1" class="reference"><a href="#cite_note-e-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </td></tr></tbody></table> <p>For mixtures (e.g., partly diluted acids in water), the acidity function depends on the composition of the mixture and has to be determined empirically. Graphs of <i>H</i><sub>0</sub> vs <a href="/wiki/Mole_fraction" title="Mole fraction">mole fraction</a> can be found in the literature for many acids.<sup id="cite_ref-poc_3-3" class="reference"><a href="#cite_note-poc-3"><span class="cite-bracket">[</span>3<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=Hammett_acidity_function&action=edit&section=3" 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"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">L. P. Hammett and A. J. Deyrup (1932) <i>J. Am. Chem. Soc.</i> 54, 2721</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">L. P. Hammett (1940). <i>Physical Organic Chemistry</i>. (McGraw-Hill)</span> </li> <li id="cite_note-poc-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-poc_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-poc_3-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-poc_3-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-poc_3-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text">Gerrylynn K. Roberts, Colin Archibald Russell. <i>Chemical History: Reviews of the Recent Literature</i>. Royal Society of Chemistry, <b>2005</b>. <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><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-85404-464-7" title="Special:BookSources/0-85404-464-7">0-85404-464-7</a>.</span> </li> <li id="cite_note-Jolly-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-Jolly_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Jolly_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">William L. Jolly, <i>Modern Inorganic Chemistry</i> (McGraw-Hill 1984), p.202-3</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><a href="/wiki/F._Albert_Cotton" title="F. Albert Cotton">F. A. Cotton</a> and G. Wilkinson, <i>Advanced Inorganic Chemistry</i> (5th edition, Wiley-Interscience 1988), p.107-9</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">G. L. Miessler and D. A. Tarr, <i>Inorganic Chemistry</i> (2nd edition, Prentice-Hall 1999), p.170-1</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"><a rel="nofollow" class="external text" href="http://www.scienceinafrica.co.za/2002/august/ph.htm">What do you mean pH = -1? Super Acids</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060923042907/http://www.scienceinafrica.co.za/2002/august/ph.htm">Archived</a> 2006-09-23 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a></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">"The Hammett Acidity Function H<sub>0</sub> for Hydrofluoric Acid Solutions." Herbert H. Hyman, Martin Kilpatrick, Joseph J. Katz, <i>J. Am. Chem. Soc.</i>, 1957, 79 (14), pp 3668–3671 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><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%2Fja01571a016">10.1021/ja01571a016</a> <a rel="nofollow" class="external free" href="http://pubs.acs.org/doi/abs/10.1021/ja01571a016">http://pubs.acs.org/doi/abs/10.1021/ja01571a016</a></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">Liang, Jack Joan-Nan, <a rel="nofollow" class="external text" href="http://hdl.handle.net/11375/8664">"The Hammett Acidity Function for Hydrofluoric Acid and some related Superacid Systems"</a> (1976). Open Access Dissertations and Theses. Paper 3850.</span> </li> <li id="cite_note-b-10"><span class="mw-cite-backlink">^ <a href="#cite_ref-b_10-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-b_10-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSaitoSaitoOhwadaShudo1991" class="citation journal cs1">Saito, Shoichi; Saito, Shin-ichi; Ohwada, Tomohiko; Shudo, Koichi (1991). "The Hammett Acidity Function H0 of Trifluoromethanesulfonic Acid-Trifluoroacetic Acid and Related Acid Systems. A Versatile Nonaqueous Acid System". <i>Chemical and Pharmaceutical Bulletin</i>. <b>39</b> (10): <span class="nowrap">2718–</span>2720. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1248%2Fcpb.39.2718">10.1248/cpb.39.2718</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chemical+and+Pharmaceutical+Bulletin&rft.atitle=The+Hammett+Acidity+Function+H0+of+Trifluoromethanesulfonic+Acid-Trifluoroacetic+Acid+and+Related+Acid+Systems.+A+Versatile+Nonaqueous+Acid+System.&rft.volume=39&rft.issue=10&rft.pages=%3Cspan+class%3D%22nowrap%22%3E2718-%3C%2Fspan%3E2720&rft.date=1991&rft_id=info%3Adoi%2F10.1248%2Fcpb.39.2718&rft.aulast=Saito&rft.aufirst=Shoichi&rft.au=Saito%2C+Shin-ichi&rft.au=Ohwada%2C+Tomohiko&rft.au=Shudo%2C+Koichi&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> <li id="cite_note-d-11"><span class="mw-cite-backlink">^ <a href="#cite_ref-d_11-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-d_11-1"><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="CITEREFVinnik1966" class="citation journal cs1">Vinnik, M. I. (1966). "Acidity Functions of Aqueous Solutions of Strong Acids". <i>Russian Chemical Reviews</i>. <b>35</b> (11): <span class="nowrap">802–</span>817. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1966RuCRv..35..802V">1966RuCRv..35..802V</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1070%2FRC1966v035n11ABEH001540">10.1070/RC1966v035n11ABEH001540</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Russian+Chemical+Reviews&rft.atitle=Acidity+Functions+of+Aqueous+Solutions+of+Strong+Acids&rft.volume=35&rft.issue=11&rft.pages=%3Cspan+class%3D%22nowrap%22%3E802-%3C%2Fspan%3E817&rft.date=1966&rft_id=info%3Adoi%2F10.1070%2FRC1966v035n11ABEH001540&rft_id=info%3Abibcode%2F1966RuCRv..35..802V&rft.aulast=Vinnik&rft.aufirst=M.+I.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" 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="CITEREFDawberWyatt1960" class="citation journal cs1">Dawber, J. G.; Wyatt, P. A. H. (1960). "718. The Hammett acidity function in aqueous nitric acid". <i>Journal of the Chemical Society (Resumed)</i>: 3589. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1039%2FJR9600003589">10.1039/JR9600003589</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+Chemical+Society+%28Resumed%29&rft.atitle=718.+The+Hammett+acidity+function+in+aqueous+nitric+acid&rft.pages=3589&rft.date=1960&rft_id=info%3Adoi%2F10.1039%2FJR9600003589&rft.aulast=Dawber&rft.aufirst=J.+G.&rft.au=Wyatt%2C+P.+A.+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> <li id="cite_note-a-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-a_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-a_13-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-a_13-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-a_13-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeel1971" class="citation thesis cs1">Peel, Terence Edward (September 1971). <a rel="nofollow" class="external text" href="http://hdl.handle.net/11375/19972"><i>The Hammett Acidity Function for Some Superacid Media</i></a> (Thesis). <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/11375%2F19972">11375/19972</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.title=The+Hammett+Acidity+Function+for+Some+Superacid+Media&rft.date=1971-09&rft_id=info%3Ahdl%2F11375%2F19972&rft.aulast=Peel&rft.aufirst=Terence+Edward&rft_id=http%3A%2F%2Fhdl.handle.net%2F11375%2F19972&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOlah2009" class="citation book cs1">Olah, George (2009). <a rel="nofollow" class="external text" href="https://chemistlibrary.files.wordpress.com/2015/05/superacid-chemistry-2ed-2009-olah.pdf"><i>Superacid Chemistry</i></a> <span class="cs1-format">(PDF)</span>. John Wiley & Sons, Inc. p. 36.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Superacid+Chemistry&rft.pages=36&rft.pub=John+Wiley+%26+Sons%2C+Inc.&rft.date=2009&rft.aulast=Olah&rft.aufirst=George&rft_id=https%3A%2F%2Fchemistlibrary.files.wordpress.com%2F2015%2F05%2Fsuperacid-chemistry-2ed-2009-olah.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiang1976" class="citation thesis cs1">Liang, Joan-Nan Jack (September 1976). <a rel="nofollow" class="external text" href="http://hdl.handle.net/11375/8664"><i>The Hammett Acidity Function for Hydrofluoric Acid and some related Superacid Systems</i></a> (Thesis). <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/11375%2F8664">11375/8664</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.title=The+Hammett+Acidity+Function+for+Hydrofluoric+Acid+and+some+related+Superacid+Systems&rft.date=1976-09&rft_id=info%3Ahdl%2F11375%2F8664&rft.aulast=Liang&rft.aufirst=Joan-Nan+Jack&rft_id=http%3A%2F%2Fhdl.handle.net%2F11375%2F8664&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> <li id="cite_note-e-16"><span class="mw-cite-backlink">^ <a href="#cite_ref-e_16-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-e_16-1"><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="CITEREFMalhotraMathewSurya_Prakash2017" class="citation journal cs1">Malhotra, Ripudaman; Mathew, Thomas; Surya Prakash, G K (December 2017). "George Andrew Olah: Across conventional lines". <i>Resonance</i>. <b>22</b> (12): <span class="nowrap">1111–</span>1153. <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%2Fs12045-017-0578-7">10.1007/s12045-017-0578-7</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Resonance&rft.atitle=George+Andrew+Olah%3A+Across+conventional+lines&rft.volume=22&rft.issue=12&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1111-%3C%2Fspan%3E1153&rft.date=2017-12&rft_id=info%3Adoi%2F10.1007%2Fs12045-017-0578-7&rft.aulast=Malhotra&rft.aufirst=Ripudaman&rft.au=Mathew%2C+Thomas&rft.au=Surya+Prakash%2C+G+K&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHammett+acidity+function" class="Z3988"></span></span> </li> </ol></div></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" 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