Isoelectronicity

<h2 id="examples">Examples</h2>

<p>The <a href="/facts/Nitrogen/Nf1QpGDz">N</a> atom and the <a href="/facts/Oxygen/acyn6o8r">O+</a> ion are isoelectronic because each has five <a href="/facts/Valence_electron/mXPA15VP">valence electrons</a>, or more accurately an electronic configuration of [He] 2s2 2p3.
</p><p>Similarly, the <a href="/facts/Cation/wrbwhF3z">cations</a> <a href="/facts/Potassium/FWPwS7Rj">K+</a>, <a href="/facts/Calcium/hf252CC0">Ca2+</a>, and <a href="/facts/Scandium/TJRt1chg">Sc3+</a> and the <a href="/facts/Anion/wrbwhF3z">anions</a> <a href="/facts/Chloride/m9NUaUDR">Cl−</a>, <a href="/facts/Sulfide/d8YMjLeu">S2−</a>, and <a href="/facts/Phosphide/u5J5Apjs">P3−</a> are all isoelectronic with the <a href="/facts/Argon/QX6NRH6d">Ar</a> atom. 
</p><p>CO, <a href="/facts/Cyanide/t0o8FMKI">CN−</a>, N2, and NO+ are isoelectronic because each has two atoms triple bonded together, and due to the charge have analogous electronic configurations (N− is identical in electronic configuration to O so CO is identical electronically to CN−).
</p><p><a href="/facts/Molecular_orbital_diagram/pJRHMzwJ">Molecular orbital diagrams</a> best illustrate isoelectronicity in diatomic molecules, showing how <a href="/facts/Atomic_orbital/tKhgl6mL">atomic orbital</a> mixing in isoelectronic species results in identical orbital combination, and thus also bonding.
</p><p>More complex molecules can be polyatomic also. For example, the <a href="/facts/Amino_acid/WDxYwBny">amino acids</a> <a href="/facts/Serine/4duVl30B">serine</a>, <a href="/facts/Cysteine/kbqvUm6d">cysteine</a>, and <a href="/facts/Selenocysteine/9ovfzrXW">selenocysteine</a> are all isoelectronic to each other. They differ by which specific <a href="/facts/Chalcogen/nXLGmnqL">chalcogen</a> is present at one location in the side-chain.
</p><p>CH3COCH3 (<a href="/facts/Acetone/cVyJxKqw">acetone</a>) and CH3N2CH3 (<a href="/facts/Azomethane/Ar5qNeTC">azomethane</a>) are not isoelectronic. They do have the same number of electrons but they do not have the same structure.
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Isolobal_principle/Vv6bh93V">Isolobal principle</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "isoelectronic". doi:10.1351/goldbook.I03276 <a href="/wiki/International_Union_of_Pure_and_Applied_Chemistry" target="_blank">/wiki/International_Union_of_Pure_and_Applied_Chemistry</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Isoelectronic Configurations Archived 2017-07-17 at the Wayback Machine iun.edu <a href="http://www.iun.edu/~cpanhd/C101webnotes/chemical-bond/isoelectronic.html" target="_blank">http://www.iun.edu/~cpanhd/C101webnotes/chemical-bond/isoelectronic.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>A. A. Aradi & T. P. Fehlner, "Isoelectronic Organometallic Molecules", in F. G. A. Stone & Robert West (eds.) Advances in Organometallic Chemistry Vol. 30 (1990), Chapter 5 (at p. 190) google books link <a href="https://books.google.com/books?id=e6R4oMRDhvsC&pg=PA190" target="_blank">https://books.google.com/books?id=e6R4oMRDhvsC&pg=PA190</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

Isoelectronicity open-in-new

Isoelectronicity