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class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Formalism used for classifying compounds</div> <p>In <a href="/wiki/Chemistry" title="Chemistry">chemistry</a>, <b>electron counting</b> is a formalism for assigning a number of <a href="/wiki/Valence_electrons" class="mw-redirect" title="Valence electrons">valence electrons</a> to individual atoms in a molecule. It is used for classifying compounds and for explaining or predicting their electronic structure and <a href="/wiki/Chemical_bond" title="Chemical bond">bonding</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> Many rules in chemistry rely on electron-counting: </p> <ul><li><a href="/wiki/Octet_rule" title="Octet rule">Octet rule</a> is used with <a href="/wiki/Lewis_structure" title="Lewis structure">Lewis structures</a> for <a href="/wiki/Main_group_element" class="mw-redirect" title="Main group element">main group elements</a>, especially the lighter ones such as <a href="/wiki/Carbon" title="Carbon">carbon</a>, <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, and <a href="/wiki/Oxygen" title="Oxygen">oxygen</a>,</li> <li><a href="/wiki/18-electron_rule" title="18-electron rule">18-electron rule</a><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> in <a href="/wiki/Inorganic_chemistry" title="Inorganic chemistry">inorganic chemistry</a> and <a href="/wiki/Organometallic_chemistry" title="Organometallic chemistry">organometallic chemistry</a> of <a href="/wiki/Transition_metal" title="Transition metal">transition metals</a>,</li> <li><a href="/wiki/H%C3%BCckel%27s_rule" title="Hückel's rule">Hückel's rule</a> for the <a href="/wiki/Pi_electron" class="mw-redirect" title="Pi electron">π-electrons</a> of <a href="/wiki/Aromaticity" title="Aromaticity">aromatic compounds</a>,</li> <li><a href="/wiki/Polyhedral_skeletal_electron_pair_theory" title="Polyhedral skeletal electron pair theory">Polyhedral skeletal electron pair theory</a> for <a href="/wiki/Polyhedron" title="Polyhedron">polyhedral</a> <a href="/wiki/Cluster_compound" class="mw-redirect" title="Cluster compound">cluster compounds</a>, including transition metals and main group elements and mixtures thereof, such as <a href="/wiki/Boranes" title="Boranes">boranes</a>.</li></ul> <p>Atoms are called "<a href="/wiki/Electron_deficiency" title="Electron deficiency">electron-deficient</a>" when they have too few electrons as compared to their respective rules, or "<a href="/wiki/Hypervalent_molecule" title="Hypervalent molecule">hypervalent</a>" when they have too many electrons. Since these compounds tend to be more reactive than compounds that obey their rule, electron counting is an important tool for identifying the reactivity of molecules. While the counting formalism considers each atom separately, these individual atoms (with their hypothetical assigned charge) do not generally exist as free <a href="/wiki/Chemical_species" title="Chemical species">species</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Counting_rules">Counting rules</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=1" title="Edit section: Counting rules"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Two methods of electron counting are "neutral counting" and "ionic counting". Both approaches give the same result (and can therefore be used to verify one's calculation). </p> <ul><li>The neutral counting approach assumes the molecule or fragment being studied consists of purely <a href="/wiki/Covalent_bond" title="Covalent bond">covalent bonds</a>. It was popularized by <a href="/wiki/Malcolm_Green_(chemist)" title="Malcolm Green (chemist)">Malcolm Green</a> along with the L and X <a href="/wiki/Ligand" title="Ligand">ligand</a> notation.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> It is usually considered easier especially for low-valent transition metals.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li>The "ionic counting" approach assumes purely <a href="/wiki/Ionic_bonding" title="Ionic bonding">ionic bonds</a> between atoms.</li></ul> <p>It is important, though, to be aware that most chemical species exist between the purely covalent and ionic extremes. </p> <div class="mw-heading mw-heading3"><h3 id="Neutral_counting">Neutral counting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=2" title="Edit section: Neutral counting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>Neutral counting assumes each bond is equally split between two atoms.</li> <li>This method begins with locating the central atom on the periodic table and determining the number of its valence electrons. One counts valence electrons for main group elements differently from transition metals, which use <a href="/wiki/D_electron_count" title="D electron count">d electron count</a>.</li></ul> <dl><dd>E.g. in period 2: B, C, N, O, and F have 3, 4, 5, 6, and 7 valence electrons, respectively.</dd> <dd>E.g. in period 4: K, Ca, Sc, Ti, V, Cr, Fe, Ni have 1, 2, 3, 4, 5, 6, 8, 10 valence electrons respectively.</dd></dl> <ul><li>One is added for every <a href="/wiki/Halide" title="Halide">halide</a> or other anionic ligand which binds to the central atom through a sigma bond.</li> <li>Two is added for every lone pair bonding to the metal (e.g. each Lewis base binds with a lone pair). Unsaturated hydrocarbons such as alkenes and alkynes are considered <a href="/wiki/Lewis_base" class="mw-redirect" title="Lewis base">Lewis bases</a>. Similarly <a href="/wiki/Lewis_acids_and_bases" title="Lewis acids and bases">Lewis</a> and <a href="/wiki/Bronsted_acid" class="mw-redirect" title="Bronsted acid">Bronsted acids</a> (protons) contribute nothing.</li> <li>One is added for each homoelement bond.</li> <li>One is added for each negative charge, and one is subtracted for each positive charge.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Ionic_counting">Ionic counting</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=3" title="Edit section: Ionic counting"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>Ionic counting assumes unequal sharing of electrons in the bond. The more electronegative atom in the bond gains electron lost from the less electronegative atom.</li> <li>This method begins by calculating the number of electrons of the element, assuming an <a href="/wiki/Oxidation_state" title="Oxidation state">oxidation state</a>.</li></ul> <dl><dd>E.g. for a Fe<sup>2+</sup> has 6 electrons</dd> <dd>S<sup>2−</sup> has 8 electrons</dd></dl> <ul><li>Two is added for every <a href="/wiki/Halide" title="Halide">halide</a> or other anionic ligand which binds to the metal through a <a href="/wiki/Sigma_bond" title="Sigma bond">sigma bond</a>.</li> <li>Two is added for every lone pair bonding to the metal (e.g. each phosphine ligand can bind with a lone pair). Similarly Lewis and Bronsted acids (protons) contribute nothing.</li> <li>For unsaturated ligands such as alkenes, one electron is added for each carbon atom binding to the metal.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Electrons_donated_by_common_fragments">Electrons donated by common fragments</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=4" title="Edit section: Electrons donated by common fragments"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable"> <tbody><tr> <th>Ligand</th> <th>Electrons contributed<br />(neutral counting)</th> <th>Electrons contributed<br />(ionic counting)</th> <th>Ionic equivalent </th></tr> <tr> <td><a href="/wiki/Halide" title="Halide">X</a></td> <td>1</td> <td>2</td> <td>X<sup>−</sup>; X = F, Cl, Br, I </td></tr> <tr> <td><a href="/wiki/Hydride" title="Hydride">H</a></td> <td>1</td> <td>2</td> <td>H<sup>−</sup> </td></tr> <tr> <td><a href="/wiki/Hydrogen" title="Hydrogen">H</a></td> <td>1</td> <td>0</td> <td>H<sup>+</sup> </td></tr> <tr> <td><a href="/wiki/Oxide" title="Oxide">O</a></td> <td>2</td> <td>4</td> <td>O<sup>2−</sup> </td></tr> <tr> <td><a href="/wiki/Nitride" title="Nitride">N</a></td> <td>3</td> <td>6</td> <td>N<sup>3−</sup> </td></tr> <tr> <td><a href="/wiki/Carbonyl_ligand" class="mw-redirect" title="Carbonyl ligand">CO</a> </td> <td>2 </td> <td>2 </td> <td>CO </td></tr> <tr> <td><a href="/wiki/Amine" title="Amine">NR<sub>3</sub></a></td> <td>2</td> <td>2</td> <td>NR<sub>3</sub>; R = H, alkyl, aryl </td></tr> <tr> <td><a href="/wiki/Alkylidene" class="mw-redirect" title="Alkylidene">CR<sub>2</sub></a></td> <td>2</td> <td>4</td> <td><style data-mw-deduplicate="TemplateStyles:r1123817410">.mw-parser-output .template-chem2-su{display:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em}.mw-parser-output .template-chem2-su>span{display:block;text-align:left}.mw-parser-output sub.template-chem2-sub{font-size:80%;vertical-align:-0.35em}.mw-parser-output sup.template-chem2-sup{font-size:80%;vertical-align:0.65em}</style><span class="chemf nowrap">CR<span class="template-chem2-su"><span>2−</span><span>2</span></span></span> </td></tr> <tr> <td><a href="/wiki/Ethylene" title="Ethylene">Ethylene</a></td> <td>2</td> <td>2</td> <td>C<sub>2</sub>H<sub>4</sub> </td></tr> <tr> <td><a href="/wiki/Cyclopentadienyl_complex" title="Cyclopentadienyl complex">cyclopentadienyl</a></td> <td>5</td> <td>6</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1123817410"><span class="chemf nowrap">C<sub class="template-chem2-sub">5</sub>H<span class="template-chem2-su"><span>−</span><span>5</span></span></span> </td></tr> <tr> <td><a href="/wiki/Benzene" title="Benzene">benzene</a></td> <td>6</td> <td>6</td> <td>C<sub>6</sub>H<sub>6</sub> </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id=""Special_cases""><span id=".22Special_cases.22"></span>"Special cases"</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=5" title="Edit section: "Special cases""><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The numbers of electrons "donated" by some ligands depends on the geometry of the metal-ligand ensemble. An example of this complication is the M–<a href="/wiki/Nitrosyl" class="mw-redirect" title="Nitrosyl">NO</a> entity. When this grouping is linear, the NO ligand is considered to be a three-electron ligand. When the M–NO subunit is strongly bent at N, the NO is treated as a pseudohalide and is thus a one electron (in the neutral counting approach). The situation is not very different from the <i>η</i><sup>3</sup> versus the <i>η</i><sup>1</sup> allyl. Another unusual ligand from the electron counting perspective is <a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=6" title="Edit section: Examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Water" title="Water">H<sub>2</sub>O</a></li></ul> <p>For a water molecule (H<sub>2</sub>O), using both neutral counting and ionic counting result in a total of 8 electrons. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Water_molecule_covalent_counting.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Water_molecule_covalent_counting.jpg/220px-Water_molecule_covalent_counting.jpg" decoding="async" width="220" height="152" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/7/7f/Water_molecule_covalent_counting.jpg 1.5x" data-file-width="235" data-file-height="162" /></a><figcaption>This figure of the water molecule shows how the electrons are distributed with the covalent counting method. The red ones are the oxygen electrons, and the blue ones are electrons from the hydrogen atoms.</figcaption></figure> <table class="wikitable"> <caption><b>Neutral counting</b> </caption> <tbody><tr> <th>Atom </th> <th>Electrons contributed </th> <th>Electron count </th></tr> <tr> <td>H<sup>.</sup> </td> <td>1 electron x 2 </td> <td>2 electrons </td></tr> <tr> <td>O </td> <td>6 electrons </td> <td>6 electrons </td></tr> <tr> <td> </td> <td> </td> <td><b>Total = 8 electrons</b> </td></tr></tbody></table> <p>The neutral counting method assumes each OH bond is split equally (each atom gets one electron from the bond). Thus both hydrogen atoms have an electron count of one. The oxygen atom has 6 valence electrons. The total electron count is 8, which agrees with the octet rule. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Water_molecule_ionic_countin.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ab/Water_molecule_ionic_countin.jpg/220px-Water_molecule_ionic_countin.jpg" decoding="async" width="220" height="143" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/a/ab/Water_molecule_ionic_countin.jpg 1.5x" data-file-width="276" data-file-height="180" /></a><figcaption>This figure of the water molecule shows how the electrons are distributed with the ionic counting method. The red ones are the oxygen electrons, and the blue ones are electrons from hydrogen. All electrons in the OH bonds belong to the more electronegative oxygen.</figcaption></figure> <table class="wikitable"> <caption>Ionic counting </caption> <tbody><tr> <th>Atom </th> <th>Electrons contributed </th> <th>Electron count </th></tr> <tr> <td>H<sup>+</sup> </td> <td>none </td> <td>0 electron </td></tr> <tr> <td>O<sup>2-</sup> </td> <td>8 electrons </td> <td>8 electrons </td></tr> <tr> <td> </td> <td> </td> <td><b>Total = 8 electrons</b> </td></tr></tbody></table> <p>With the ionic counting method, the more electronegative oxygen will gain electrons donated by the two hydrogen atoms in the two OH bonds to become O<sup>2-</sup>. It now has 8 total valence electrons, which obeys the octet rule. </p> <ul><li><a href="/wiki/Methane" title="Methane">CH<sub>4</sub></a>, for the central C</li></ul> <dl><dd>neutral counting: C contributes 4 electrons, each H radical contributes one each: 4 + 4 × 1 = 8 valence electrons</dd> <dd>ionic counting: C<sup>4−</sup> contributes 8 electrons, each proton contributes 0 each: 8 + 4 × 0 = 8 electrons.</dd> <dd>Similar for H:</dd> <dd>neutral counting: H contributes 1 electron, the C contributes 1 electron (the other 3 electrons of C are for the other 3 hydrogens in the molecule): 1 + 1 × 1 = 2 valence electrons.</dd> <dd>ionic counting: H contributes 0 electrons (H<sup>+</sup>), C<sup>4−</sup> contributes 2 electrons (per H), 0 + 1 × 2 = 2 valence electrons</dd> <dd>conclusion: Methane follows the octet-rule for carbon, and the duet rule for hydrogen, and hence is expected to be a stable molecule (as we see from daily life)</dd></dl> <ul><li><a href="/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">H<sub>2</sub>S</a>, for the central S</li></ul> <dl><dd>neutral counting: S contributes 6 electrons, each hydrogen radical contributes one each: 6 + 2 × 1 = 8 valence electrons</dd> <dd>ionic counting: S<sup>2−</sup> contributes 8 electrons, each proton contributes 0: 8 + 2 × 0 = 8 valence electrons</dd> <dd>conclusion: with an octet electron count (on sulfur), we can anticipate that H<sub>2</sub>S would be pseudo-tetrahedral if one considers the two lone pairs.</dd></dl> <ul><li><a href="/wiki/Sulfur_dichloride" title="Sulfur dichloride">SCl<sub>2</sub></a>, for the central S</li></ul> <dl><dd>neutral counting: S contributes 6 electrons, each chlorine radical contributes one each: 6 + 2 × 1 = 8 valence electrons</dd> <dd>ionic counting: S<sup>2+</sup> contributes 4 electrons, each chloride anion contributes 2: 4 + 2 × 2 = 8 valence electrons</dd> <dd>conclusion: see discussion for H<sub>2</sub>S above. Both SCl<sub>2</sub> and H<sub>2</sub>S follow the octet rule - the behavior of these molecules is however quite different.</dd></dl> <ul><li><a href="/wiki/Sulfur_hexafluoride" title="Sulfur hexafluoride">SF<sub>6</sub></a>, for the central S</li></ul> <dl><dd>neutral counting: S contributes 6 electrons, each fluorine radical contributes one each: 6 + 6 × 1 = 12 valence electrons</dd> <dd>ionic counting: S<sup>6+</sup> contributes 0 electrons, each fluoride anion contributes 2: 0 + 6 × 2 = 12 valence electrons</dd> <dd>conclusion: ionic counting indicates a molecule lacking lone pairs of electrons, therefore its structure will be octahedral, as predicted by <a href="/wiki/VSEPR" class="mw-redirect" title="VSEPR">VSEPR</a>. One might conclude that this molecule would be highly reactive - but the opposite is true: SF<sub>6</sub> is inert, and it is widely used in industry because of this property.</dd></dl> <ul><li><a href="/wiki/Cis-Dichlorobis(bipyridine)ruthenium(II)" title="Cis-Dichlorobis(bipyridine)ruthenium(II)">RuCl<sub>2</sub>(bpy)<sub>2</sub></a></li></ul> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:RuCl2(bpy)2.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5d/RuCl2%28bpy%292.jpg/220px-RuCl2%28bpy%292.jpg" decoding="async" width="220" height="249" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5d/RuCl2%28bpy%292.jpg/330px-RuCl2%28bpy%292.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5d/RuCl2%28bpy%292.jpg/440px-RuCl2%28bpy%292.jpg 2x" data-file-width="613" data-file-height="695" /></a><figcaption>The geometry of <i>cis</i>-Dichlorobis(bipyridine)ruthenium(II).</figcaption></figure> <p>RuCl<sub>2</sub>(bpy)<sub>2</sub> is an octahedral metal complex with two <a href="/wiki/Bidentate" class="mw-redirect" title="Bidentate">bidentate</a> <a href="/wiki/2,2%E2%80%B2-Bipyridine" title="2,2′-Bipyridine">2,2′-Bipyridine</a> (bpy) ligands and two chloride ligands. </p> <table class="wikitable"> <caption><b>Neutral counting</b> </caption> <tbody><tr> <td><b>Metal/ligand</b> </td> <td><b>Electrons contributed</b> </td> <td><b>Electron count</b> </td></tr> <tr> <td>Ru(0) </td> <td>d<sup>8</sup> (8 d electrons) </td> <td>8 electrons </td></tr> <tr> <td>bpy </td> <td>4 electrons x 2 </td> <td>8 electrons </td></tr> <tr> <td>Cl <sup>.</sup> </td> <td>1 electron x 2 </td> <td>2 electrons </td></tr> <tr> <td> </td> <td> </td> <td><b>Total = 18 electrons</b> </td></tr></tbody></table> <p>In the neutral counting method, the Ruthenium of the complex is treated as Ru(0). It has 8 d electrons to contribute to the electron count. The two bpy ligands are <a href="/wiki/L-type_ligand" class="mw-redirect" title="L-type ligand">L-type ligand</a> neutral ligands, thus contributing two electrons each. The two chloride ligands hallides and thus 1 electron donors, donating 1 electron each to the electron count. The total electron count of RuCl<sub>2</sub>(bpy)<sub>2</sub> is 18. </p> <table class="wikitable"> <caption><b>Ionic counting</b> </caption> <tbody><tr> <td><b>metal/ligand</b> </td> <td><b>electrons contributed</b> </td> <td><b>number of electrons</b> </td></tr> <tr> <td>Ru(II) </td> <td>d<sup>6</sup> (6 d electrons) </td> <td>6 electrons </td></tr> <tr> <td>bpy </td> <td>4 electrons x 2 </td> <td>8 electrons </td></tr> <tr> <td>Cl<sup>-</sup> </td> <td>2 electrons x 2 </td> <td>4 electrons </td></tr> <tr> <td> </td> <td> </td> <td><b>Total = 18 electrons</b> </td></tr></tbody></table> <p>In the ionic counting method, the Ruthenium of the complex is treated as Ru(II). It has 6 d electrons to contribute to the electron count. The two bpy ligands are <a href="/wiki/L-type_ligand" class="mw-redirect" title="L-type ligand">L-type ligand</a> neutral ligands, thus contributing two electrons each. The two chloride ligands are anionic ligands, thus donating 2 electrons each to the electron count. The total electron count of RuCl<sub>2</sub>(bpy)<sub>2</sub> is 18, agreeing with the result of neural counting. </p> <ul><li><a href="/wiki/Titanium_tetrachloride" title="Titanium tetrachloride">TiCl<sub>4</sub></a>, for the central Ti</li></ul> <dl><dd>neutral counting: Ti contributes 4 electrons, each chlorine radical contributes one each: 4 + 4 × 1 = 8 valence electrons</dd> <dd>ionic counting: Ti<sup>4+</sup> contributes 0 electrons, each chloride anion contributes two each: 0 + 4 × 2 = 8 valence electrons</dd> <dd>conclusion: Having only 8e (vs. <a href="/wiki/Eighteen_electron_rule" class="mw-redirect" title="Eighteen electron rule">18</a> possible), we can anticipate that TiCl<sub>4</sub> will be a good Lewis acid. Indeed, it reacts (in some cases violently) with water, alcohols, ethers, amines.</dd></dl> <ul><li><a href="/wiki/Iron_pentacarbonyl" title="Iron pentacarbonyl">Fe(CO)<sub>5</sub></a></li></ul> <dl><dd>neutral counting: Fe contributes 8 electrons, each CO contributes 2 each: 8 + 2 × 5 = 18 valence electrons</dd> <dd>ionic counting: Fe(0) contributes 8 electrons, each CO contributes 2 each: 8 + 2 × 5 = 18 valence electrons</dd> <dd>conclusions: this is a special case, where ionic counting is the same as neutral counting, all fragments being neutral. Since this is an 18-electron complex, it is expected to be isolable compound.</dd></dl> <ul><li><a href="/wiki/Ferrocene" title="Ferrocene">Ferrocene, (C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>Fe</a>, for the central Fe:</li></ul> <dl><dd>neutral counting: Fe contributes 8 electrons, the 2 <a href="/wiki/Cyclopentadienyl_complex" title="Cyclopentadienyl complex">cyclopentadienyl-rings</a> contribute 5 each: 8 + 2 × 5 = 18 electrons</dd> <dd>ionic counting: Fe<sup>2+</sup> contributes 6 electrons, the two aromatic cyclopentadienyl rings contribute 6 each: 6 + 2 × 6 = 18 valence electrons on iron.</dd> <dd>conclusion: Ferrocene is expected to be an isolable compound.</dd></dl> <p><br /> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Electron_counting&action=edit&section=7" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/D_electron_count" title="D electron count">d electron count</a></li> <li><a href="/wiki/Tolman%27s_rule" title="Tolman's rule">Tolman's rule</a></li></ul> <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=Electron_counting&action=edit&section=8" 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"><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"><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="CITEREFParkin2006" class="citation journal cs1">Parkin, Gerard (2006). <a rel="nofollow" class="external text" href="http://jchemed.chem.wisc.edu/Journal/Issues/2006/May/abs791.html">"Valence, Oxidation Number, and Formal Charge: Three Related but Fundamentally Different Concepts"</a>. <i>Journal of Chemical Education</i>. <b>83</b> (5): 791. <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/2006JChEd..83..791P">2006JChEd..83..791P</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%2Fed083p791">10.1021/ed083p791</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0021-9584">0021-9584</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2009-11-10</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=Valence%2C+Oxidation+Number%2C+and+Formal+Charge%3A+Three+Related+but+Fundamentally+Different+Concepts&rft.volume=83&rft.issue=5&rft.pages=791&rft.date=2006&rft.issn=0021-9584&rft_id=info%3Adoi%2F10.1021%2Fed083p791&rft_id=info%3Abibcode%2F2006JChEd..83..791P&rft.aulast=Parkin&rft.aufirst=Gerard&rft_id=http%3A%2F%2Fjchemed.chem.wisc.edu%2FJournal%2FIssues%2F2006%2FMay%2Fabs791.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AElectron+counting" class="Z3988"></span></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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRasmussen2015" class="citation journal cs1">Rasmussen, Seth C. (March 2015). <a rel="nofollow" class="external text" href="http://link.springer.com/10.1007/s40828-015-0010-4">"The 18-electron rule and electron counting in transition metal compounds: theory and application"</a>. <i>ChemTexts</i>. <b>1</b> (1). <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%2Fs40828-015-0010-4">10.1007/s40828-015-0010-4</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2199-3793">2199-3793</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=ChemTexts&rft.atitle=The+18-electron+rule+and+electron+counting+in+transition+metal+compounds%3A+theory+and+application&rft.volume=1&rft.issue=1&rft.date=2015-03&rft_id=info%3Adoi%2F10.1007%2Fs40828-015-0010-4&rft.issn=2199-3793&rft.aulast=Rasmussen&rft.aufirst=Seth+C.&rft_id=http%3A%2F%2Flink.springer.com%2F10.1007%2Fs40828-015-0010-4&rfr_id=info%3Asid%2Fen.wikipedia.org%3AElectron+counting" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreen1995" class="citation journal cs1">Green, M. L. H. (1995-09-20). "A new approach to the formal classification of covalent compounds of the elements". <i><a href="/wiki/Journal_of_Organometallic_Chemistry" title="Journal of Organometallic Chemistry">Journal of Organometallic Chemistry</a></i>. <b>500</b> (1–2): 127–148. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-328X%2895%2900508-N">10.1016/0022-328X(95)00508-N</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0022-328X">0022-328X</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+Organometallic+Chemistry&rft.atitle=A+new+approach+to+the+formal+classification+of+covalent+compounds+of+the+elements&rft.volume=500&rft.issue=1%E2%80%932&rft.pages=127-148&rft.date=1995-09-20&rft_id=info%3Adoi%2F10.1016%2F0022-328X%2895%2900508-N&rft.issn=0022-328X&rft.aulast=Green&rft.aufirst=M.+L.+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AElectron+counting" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreen1995" class="citation journal cs1">Green, M. L. H. (1995-09-20). <a rel="nofollow" class="external text" href="https://dx.doi.org/10.1016/0022-328X%2895%2900508-N">"A new approach to the formal classification of covalent compounds of the elements"</a>. <i>Journal of Organometallic Chemistry</i>. <b>500</b> (1): 127–148. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-328X%2895%2900508-N">10.1016/0022-328X(95)00508-N</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0022-328X">0022-328X</a>.</cite><span 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style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><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:Chemical_bonds" title="Template:Chemical bonds"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Chemical_bonds" title="Template talk:Chemical bonds"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Chemical_bonds" title="Special:EditPage/Template:Chemical bonds"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Chemical_bonds" style="font-size:114%;margin:0 4em"><a href="/wiki/Chemical_bond" title="Chemical bond">Chemical bonds</a></div></th></tr><tr><th scope="row" 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two-electron bond">8c–2e</a></li></ul></li> <li><a href="/wiki/Hypervalent_molecule" title="Hypervalent molecule">Hypervalence</a> <ul><li><a href="/wiki/Three-center_four-electron_bond" title="Three-center four-electron bond">3c–4e</a></li></ul></li> <li><a href="/wiki/Agostic_interaction" title="Agostic interaction">Agostic</a></li> <li><a href="/wiki/Bent_bond" title="Bent bond">Bent</a></li> <li><a href="/wiki/Coordinate_covalent_bond" title="Coordinate covalent bond">Coordinate (dipolar)</a></li> <li><a href="/wiki/Pi_backbonding" title="Pi backbonding">Pi backbond</a></li> <li><a href="/wiki/Metal%E2%80%93ligand_multiple_bond" title="Metal–ligand multiple bond">Metal–ligand multiple bond</a></li> <li><a href="/wiki/Charge-shift_bond" title="Charge-shift bond">Charge-shift</a></li> <li><a href="/wiki/Hapticity" title="Hapticity">Hapticity</a></li> <li><a href="/wiki/Conjugated_system" title="Conjugated system">Conjugation</a></li> <li><a href="/wiki/Hyperconjugation" 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</div></td></tr></tbody></table><div></div></td><td class="noviewer navbox-image" rowspan="4" style="width:1px;padding:0 0 0 2px"><div><span typeof="mw:File"><a href="/wiki/File:Ligatio-covalens.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/21/Ligatio-covalens.svg/200px-Ligatio-covalens.svg.png" decoding="async" width="200" height="89" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/21/Ligatio-covalens.svg/300px-Ligatio-covalens.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/21/Ligatio-covalens.svg/400px-Ligatio-covalens.svg.png 2x" data-file-width="597" data-file-height="265" /></a></span><br /><span typeof="mw:File"><a href="/wiki/File:Chemfm_carbon_monoxide_3_1.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/77/Chemfm_carbon_monoxide_3_1.svg/200px-Chemfm_carbon_monoxide_3_1.svg.png" decoding="async" width="200" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/77/Chemfm_carbon_monoxide_3_1.svg/300px-Chemfm_carbon_monoxide_3_1.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/77/Chemfm_carbon_monoxide_3_1.svg/400px-Chemfm_carbon_monoxide_3_1.svg.png 2x" data-file-width="99" data-file-height="56" /></a></span><br /><span typeof="mw:File"><a href="/wiki/File:Pi-Bond.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Pi-Bond.svg/200px-Pi-Bond.svg.png" decoding="async" width="200" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Pi-Bond.svg/300px-Pi-Bond.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Pi-Bond.svg/400px-Pi-Bond.svg.png 2x" data-file-width="1920" data-file-height="1080" /></a></span></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Intermolecular_force" title="Intermolecular force">Intermolecular</a><br />(weak)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" 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/Van_der_Waals_force" title="Van der Waals force">Van der Waals<br />forces</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/London_dispersion_force" title="London dispersion force">London dispersion</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Hydrogen_bond" title="Hydrogen bond">Hydrogen</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/Low-barrier_hydrogen_bond" title="Low-barrier hydrogen bond">Low-barrier</a></li> <li><a href="/wiki/Resonance-assisted_hydrogen_bond" class="mw-redirect" title="Resonance-assisted hydrogen bond">Resonance-assisted</a></li> <li><a href="/wiki/Symmetric_hydrogen_bond" title="Symmetric hydrogen bond">Symmetric</a></li> <li><a href="/wiki/Dihydrogen_bond" title="Dihydrogen bond">Dihydrogen bonds</a></li> <li><a href="/wiki/C%E2%80%93H%C2%B7%C2%B7%C2%B7O_interaction" title="C–H···O interaction">C–H···O interaction</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Non-covalent_interactions" class="mw-redirect" title="Non-covalent interactions">Noncovalent</a><br />other</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/Mechanically_interlocked_molecular_architectures" title="Mechanically interlocked molecular architectures">Mechanical</a></li> <li><a href="/wiki/Halogen_bond" title="Halogen bond">Halogen</a></li> <li><a href="/wiki/Chalcogen_bond" title="Chalcogen bond">Chalcogen</a></li> <li><a href="/wiki/Metallophilic_interaction" title="Metallophilic interaction">Metallophilic</a> (<a href="/wiki/Aurophilicity" title="Aurophilicity">aurophilic</a>)</li> <li><a href="/wiki/Intercalation_(chemistry)" title="Intercalation (chemistry)">Intercalation</a></li> <li><a href="/wiki/Stacking_(chemistry)" title="Stacking (chemistry)">Stacking</a></li> <li><a href="/wiki/Cation%E2%80%93pi_interaction" class="mw-redirect" title="Cation–pi interaction">Cation–pi</a></li> <li><a href="/wiki/Cation%E2%80%93pi_interaction#Anion–π_interaction" class="mw-redirect" title="Cation–pi interaction">Anion–pi</a></li> <li><a href="/wiki/Salt_bridge_(protein_and_supramolecular)" title="Salt bridge (protein and supramolecular)">Salt bridge</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Bond_cleavage" title="Bond cleavage">Bond cleavage</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Heterolysis_(chemistry)" title="Heterolysis (chemistry)">Heterolysis</a></li> <li><a href="/wiki/Homolysis_(chemistry)" title="Homolysis (chemistry)">Homolysis</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Electron counting</a> rules</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Aromaticity" title="Aromaticity">Aromaticity</a> <ul><li><a href="/wiki/H%C3%BCckel%27s_rule" title="Hückel's rule">Hückel's rule</a></li> <li><a href="/wiki/Baird%27s_rule" title="Baird's rule">Baird's rule</a></li> <li><a href="/wiki/M%C3%B6bius_aromaticity" title="Möbius aromaticity">Möbius</a></li> <li><a href="/wiki/Spherical_aromaticity" title="Spherical aromaticity">spherical</a></li></ul></li> <li><a href="/wiki/Polyhedral_skeletal_electron_pair_theory" title="Polyhedral skeletal electron pair theory">Polyhedral skeletal electron pair theory</a></li> <li><a href="/wiki/Jemmis_mno_rules" title="Jemmis mno rules">Jemmis mno rules</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Electron_counting&oldid=1247026724">https://en.wikipedia.org/w/index.php?title=Electron_counting&oldid=1247026724</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a 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