In chemistry, an arsenide is a compound of arsenic with a less electronegative element or elements. Many metals form binary compounds containing arsenic, and these are called arsenides. They exist with many stoichiometries, and in this respect arsenides are similar to phosphides.
Alkali metal and alkaline earth arsenides
The group 1 alkali metals and the group 2, alkaline earth metals, form arsenides with isolated arsenic atoms. They form upon heating arsenic powder with excess sodium gives sodium arsenide (Na<sub>3</sub>As). The structure of Na<sub>3</sub>As is complex with unusually short Na–Na distances of 328–330 pm which are shorter than in sodium metal. This short distance indicates the complex bonding in these simple phases, i.e. they are not simply salts of As<sup>3−</sup> anion, for example. Cd<sub>3</sub>As<sub>2</sub>, Zn<sub>3</sub>As<sub>2</sub> and other compounds of the Zn-Cd-P-As quaternary system have very similar crystalline structures, which can be considered distorted mixtures of the zincblende and antifluorite crystalline structures.
Polyarsenides
Transition metal arsenides
Arsenic anionics are known to catenate, that is, form chains, rings, and cages. The mineral skutterudite (CoAs<sub>3</sub>) features rings that are usually described as .]]
Partial reduction of arsenic with alkali metals (and related electropositive elements) affords polyarsenic compounds, which are members of the Zintl phases.
See also
- See :Category:Arsenides for a list.