Editing Rubidium (section)

===Compounds===
{{category see also|Rubidium compounds}}
[[File:Rb9O2 cluster.png|thumb|left|upright=0.5|{{chem|Rb|9|O|2}} cluster|alt= The ball-and-stick diagram shows two regular octahedra which are connected to each other by one face. All nine vertices of the structure are purple spheres representing rubidium, and at the centre of each octahedron is a small red sphere representing oxygen.]]
[[Rubidium chloride]] (RbCl) is probably the most used rubidium compound: among several other chlorides, it is used to induce living cells to take up [[DNA]]; it is also used as a biomarker, because in nature, it is found only in small quantities in living organisms and when present, replaces potassium. Other common rubidium compounds are the corrosive [[rubidium hydroxide]] (RbOH), the starting material for most rubidium-based chemical processes; [[rubidium carbonate]] (Rb<sub>2</sub>CO<sub>3</sub>), used in some optical glasses, and rubidium copper sulfate, Rb<sub>2</sub>SO<sub>4</sub>·CuSO<sub>4</sub>·6H<sub>2</sub>O. [[Rubidium silver iodide]] (RbAg<sub>4</sub>I<sub>5</sub>) has the highest [[room temperature]] [[electrical conductivity|conductivity]] of any known [[ionic crystal]], a property exploited in thin film [[battery (electricity)|batteries]] and other applications.<ref>{{Cite book |chapter-url = https://books.google.com/books?id=pVw98i6gtwMC&pg=PA176 |title = Solid state chemistry: an introduction |chapter = RbAg<sub>4</sub>I<sub>5</sub> |first = Lesley |last = Smart |author2 = Moore, Elaine |publisher = CRC Press |date = 1995 |isbn = 978-0-7487-4068-0 |pages = [https://archive.org/details/solidstatechemis00smar_0/page/176 176–177] |url-access = registration |url = https://archive.org/details/solidstatechemis00smar_0/page/176 }}</ref><ref>{{Cite journal |title = Relationship of structure and ionic mobility in solid MAg<sub>4</sub>I<sub>5</sub> |first = J. N. |last = Bradley |author2=Greene, P. D. |journal = Trans. Faraday Soc. |date = 1967 |volume = 63 |pages = 2516 |doi = 10.1039/TF9676302516}}</ref>

Rubidium forms a number of [[Rubidium oxide|oxides]] when exposed to air, including rubidium monoxide (Rb<sub>2</sub>O), Rb<sub>6</sub>O, and Rb<sub>9</sub>O<sub>2</sub>; rubidium in excess oxygen gives the [[superoxide]] [[Rubidium superoxide|RbO<sub>2</sub>]]. Rubidium forms salts with halogens, producing [[rubidium fluoride]], [[rubidium chloride]], [[rubidium bromide]], and [[rubidium iodide]].<ref name=G&W>{{Greenwood&Earnshaw2nd}}</ref>