Editing Silver (section)

===Oxides and chalcogenides===
[[File:Sulfid stříbrný.PNG|thumb|right|Silver(I) sulfide]]
Silver and gold have rather low [[chemical affinity|chemical affinities]] for oxygen, lower than copper, and it is therefore expected that silver oxides are thermally quite unstable. Soluble silver(I) salts precipitate dark-brown [[silver(I) oxide]], Ag<sub>2</sub>O, upon the addition of alkali. (The hydroxide AgOH exists only in solution; otherwise it spontaneously decomposes to the oxide.) Silver(I) oxide is very easily reduced to metallic silver, and decomposes to silver and oxygen above 160&nbsp;°C.<ref name="Greenwood and Earnshaw-9">Greenwood and Earnshaw, pp. 1181–82</ref> This and other silver(I) compounds may be oxidised by the strong oxidising agent [[peroxodisulfate]] to black AgO, a mixed [[silver(I,III) oxide]] of formula Ag<sup>I</sup>Ag<sup>III</sup>O<sub>2</sub>. Some other mixed oxides with silver in non-integral oxidation states, namely Ag<sub>2</sub>O<sub>3</sub> and Ag<sub>3</sub>O<sub>4</sub>, are also known, as is Ag<sub>3</sub>O which behaves as a metallic conductor.<ref name="Greenwood and Earnshaw-9" />

[[Silver(I) sulfide]], Ag<sub>2</sub>S, is very readily formed from its constituent elements and is the cause of the black tarnish on some old silver objects. It may also be formed from the reaction of [[hydrogen sulfide]] with silver metal or aqueous Ag<sup>+</sup> ions. Many non-stoichiometric [[selenide]]s and [[telluride (chemistry)|tellurides]] are known; in particular, AgTe<sub>~3</sub> is a low-temperature [[superconductor]].<ref name="Greenwood and Earnshaw-9" />