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Rubidium oxide
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<h2 id="properties">Properties</h2> <p>Like other alkali metal oxides, Rb2O is a strong <a href="/facts/Base_(chemistry)/M9wA7qeM">base</a>. Thus, Rb2O reacts exothermically with water to form <a href="/facts/Rubidium_hydroxide/T9fnSIKz">rubidium hydroxide</a>. </p> Rb2O + H2O → 2 RbOH <p>So reactive is Rb2O toward water that it is considered <a href="/facts/Hygroscopic/1NBGewXv">hygroscopic</a>. Upon heating, Rb2O reacts with <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> to rubidium hydroxide and <a href="/facts/Rubidium_hydride/37RvT8xV">rubidium hydride</a>:<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> </p> Rb2O + H2 → RbOH + RbH <h2 id="synthesis">Synthesis</h2> <p>For laboratory use, RbOH is usually used in place of the oxide. RbOH can be purchased for ca. <a href="/facts/US%24/naEEDUhC">US$</a>5/g (2006). The hydroxide is more useful, less reactive toward atmospheric moisture, and less expensive than the oxide. </p><p>As for most alkali metal oxides,<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> the best synthesis of Rb2O does <i>not</i> entail oxidation of the metal but reduction of the anhydrous nitrate: </p> 10 Rb + 2 RbNO3 → 6 Rb2O + N2 <p>Typical for alkali metal hydroxides, RbOH <i>cannot</i> be dehydrated to the oxide. Instead, the hydroxide can be decomposed to the oxide (by reduction of the hydrogen ion) using Rb metal: </p> 2 Rb + 2 RbOH → 2 Rb2O + H2 <p>Metallic Rb reacts with O2, as indicated by its tendency to rapidly <a href="/facts/Tarnish/GCskvFrN">tarnish</a> in air. The tarnishing process is relatively colorful as it proceeds via bronze-colored Rb6O and copper-colored Rb9O2.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> The <a href="/facts/Suboxide/UnVJWcwX">suboxides</a> of rubidium that have been characterized by <a href="/facts/X-ray_crystallography/WtI0F5DN">X-ray crystallography</a> include Rb9O2 and Rb6O, as well as the mixed <a href="/facts/Caesium/dXKN1S5k">Cs</a>-Rb suboxides Cs11O3Rb<i>n</i> (<i>n</i> = 1, 2, 3).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p><p>The final product of oxygenation of Rb is principally RbO2, <a href="/facts/Rubidium_superoxide/paBsQaFT">rubidium superoxide</a>: </p> Rb + O2 → RbO2 <p>This superoxide can then be reduced to Rb2O using excess rubidium metal: </p> 3 Rb + RbO2 → 2 Rb2O <h2 id="further-reading">Further reading</h2> <ul><li><a href="https://web.archive.org/web/20111211122709/http://www.diracdelta.co.uk/science/source/r/u/rubidium%20oxide/source.html">"Rubidium Oxide"</a>. <i>DiracDelta.co.uk science and engineering encyclopedia</i>. Dirac Delta Consultants. Archived from <a href="http://www.diracdelta.co.uk/science/source/r/u/rubidium%20oxide/source.html">the original</a> on 11 December 2011. Retrieved 16 November 2011.</li> <li><a href="http://www.webelements.com/compounds/rubidium/dirubidium_oxide.html">"Rubidium compounds: dirubidium oxide"</a>. <i>WebElements: the periodic table on the web</i>. WebElements. Retrieved 16 November 2011.</li> <li><a href="https://web.archive.org/web/20120418221715/http://www.fishersci.com/ecomm/servlet/fsproductdetail?LBCID=67207776&storeId=10652&aid=221420">"Rubidium Oxide"</a>. <i>fishersci.com</i>. Thermo Fisher Scientific. Archived from <a href="http://www.fishersci.com/ecomm/servlet/fsproductdetail?LBCID=67207776&storeId=10652&aid=221420">the original</a> on 18 April 2012. Retrieved 16 November 2011.</li></ul> Wikimedia Commons has media related to Rubidium oxide. <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Wells, Alexander Frank (1984). Structural Inorganic Chemistry (5th ed.). Oxford: Clarendon Press. ISBN 978-0-19-855370-0. <a href="978-0-19-855370-0" target="_blank">978-0-19-855370-0</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Nechamkin, Howard (1968). The chemistry of the elements. New York: McGraw-Hill. p. 34. <a href="https://archive.org/details/chemistryofeleme00nech" target="_blank">https://archive.org/details/chemistryofeleme00nech</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Holleman, A.F.; Wiberg, E., eds. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 978-0-12-352651-9. <a href="978-0-12-352651-9" target="_blank">978-0-12-352651-9</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Holleman, A.F.; Wiberg, E., eds. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 978-0-12-352651-9. <a href="978-0-12-352651-9" target="_blank">978-0-12-352651-9</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Simon, A. (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>