Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Isoelectronicity
open-in-new
<p>Isoelectronicity is a <a href="/facts/Phenomenon/4CBrlVeW">phenomenon</a> observed when two or more <a href="/facts/Molecule/N9ljSfFq">molecules</a> have the same <a href="/facts/Chemical_structure/r5rT1Lj4">structure</a> (positions and connectivities among <a href="/facts/Atom/FoQ4kGN5">atoms</a>) and the same <a href="/facts/Electron_configuration/TQjRr22P">electronic configurations</a>, but differ by what specific <a href="/facts/Chemical_element/0jducgWD">elements</a> are at certain locations in the structure. For example, <a href="/facts/Carbon_monoxide/CKuLtEMJ">CO</a>, <a href="/facts/Nitrosonium/zmRlEu1k">NO+</a>, and <a href="/facts/Nitrogen/Nf1QpGDz">N2</a> are isoelectronic, while <a href="/facts/Acetone/cVyJxKqw">CH3COCH3</a> and CH3N=NCH3 are not. </p><p>This definition is sometimes termed valence isoelectronicity. Definitions can sometimes be not as strict, sometimes requiring identity of the total <a href="/facts/Electron/L0KBo5cW">electron</a> count and with it the entire <a href="/facts/Electron_configuration/TQjRr22P">electronic configuration</a>. More usually, definitions are broader, and may extend to allowing different numbers of atoms in the <a href="/facts/Chemical_species/A8BxM3oW">species</a> being compared. </p><p>The importance of the concept lies in identifying significantly related species, as pairs or series. Isoelectronic species can be expected to show useful consistency and predictability in their properties, so identifying a compound as isoelectronic with one already characterised offers clues to possible properties and reactions. Differences in properties such as <a href="/facts/Electronegativity/H7Vq7Uah">electronegativity</a> of the atoms in isolelectronic species can affect reactivity. </p><p>In <a href="/facts/Quantum_mechanics/BRc3Mzgr">quantum mechanics</a>, <a href="/facts/Hydrogen-like_atom/0rmuVpjT">hydrogen-like atoms</a> are <a href="/facts/Ion/3bePpDna">ions</a> with only one electron such as <a href="/facts/Lithium/7vXX6BWA">Li2+</a>. These ions would be described as being isoelectronic with <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a>. </p>