Suboxide

<h2 id="metal-containing-suboxides">Metal-containing suboxides</h2>
<p>Suboxides are intermediates along the pathway that forms the normal oxide.  Suboxides are sometimes visible when certain metals are exposed to small amounts of <a href="/facts/Oxygen/acyn6o8r">O2</a>:
</p>
22 Cs  +  3 O2  →  2 Cs11O3
4 Cs11O3  +  5 O2  →  22 Cs2O
<p>Several suboxides of <a href="/facts/Caesium/dXKN1S5k">caesium</a> and rubidium have been characterized by <a href="/facts/X-ray_crystallography/WtI0F5DN">X-ray crystallography</a>. As of 1997, the inventory includes the following Rb9O2, Rb6O, Cs11O3, Cs4O, Cs7O, Cs11O3Rb, Cs11O3Rb2, and Cs11O3Rb3.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
</p><p>Suboxides are generally colored compounds indicating a degree of electron delocalisation. Cs7O has a unit cell containing a Cs11O3 cluster and 10 Cs atoms. The cluster can be visualised as being composed of three face-sharing octahedra. In the picture below the caesium atoms are purple and the oxygen atoms are red. The Cs-Cs distance in the cluster is 376 pm, which is less than the Cs-Cs distance in the metal of 576 pm. Rb9O2 and Rb6O both contain the Rb9O2 cluster, which can be visualised as two face-sharing octahedra. Rb6O can be formulated as (Rb9O2)Rb3. The Rb-Rb distance in the cluster is 352 pm which is shorter than the Rb-Rb in the metal of 485 pm. It is suggested that caesium suboxides play a role in the Ag-O-Cs (S1) and multialkali Na-K-Sb-Cs <a href="/facts/Photocathode/XPcNlAjs">photocathodes</a>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
<table><tbody><tr><td></td><td></td></tr><tr><td>Rb9O2 cluster</td><td>Cs11O3 cluster</td></tr></tbody></table>
<h2 id="carbon-suboxide">Carbon suboxide</h2>
<p>The suboxide of carbon adopts an unremarkable structure.  As for related organic <a href="/facts/Cumulene/UtxYSvxN">cumulenes</a> (e.g. <a href="/facts/Ketene/ByPehuE4">ketene</a>), C3O2 obeys the <a href="/facts/Octet_rule/X9jxSsos">octet rule</a>.
</p>
<h2 id="related-compounds">Related compounds</h2>
<p><a href="/facts/Subnitride/AXDWnmSh">Subnitrides</a> are also known. For example, Na16Ba6N features a <a href="/facts/Nitride/9vkrCbJ4">nitride</a>-centered <a href="/facts/Octahedral/G38q92xW">octahedral</a> <a href="/facts/Cluster_chemistry/EsuLgxJU">cluster</a> of six <a href="/facts/Barium/IkL09XHQ">barium</a> atoms embedded in a matrix of sodium.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p>

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

<ol>
<li id="fn:1"><p>Simon, Arndt (1997). "Group 1 and 2 suboxides and subnitrides — Metals with atomic size holes and tunnels". Coordination Chemistry Reviews. 163: 253–270. doi:10.1016/S0010-8545(97)00013-1. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Greenwood, Norman  N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Simon, Arndt (1997). "Group 1 and 2 suboxides and subnitrides — Metals with atomic size holes and tunnels". Coordination Chemistry Reviews. 163: 253–270. doi:10.1016/S0010-8545(97)00013-1. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>King, R Bruce, ed. (1994) Oxides: solid state chemistry, Vol. 6 of WH McCarrroll Encyclopedia of Inorganic chemistry. John Wiley and Sons. ISBN 0-471-93620-0 <a href="/wiki/ISBN_(identifier)" target="_blank">/wiki/ISBN_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Simon, Arndt (1997). "Group 1 and 2 suboxides and subnitrides — Metals with atomic size holes and tunnels". Coordination Chemistry Reviews. 163: 253–270. doi:10.1016/S0010-8545(97)00013-1. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
</ol>

Suboxide open-in-new

Suboxide