Chromium Sesqui-arsenide, Cr₂As₃

Chromium Sesqui-arsenide, Cr₂As₃, is prepared by heating finely divided chromium with excess of arsenic at 700° C. in a sealed exhausted tube, the product being powdered and again heated. The resulting compound is not changed in composition by prolonged heating in hydrogen at 400° C., but above that temperature it loses arsenic and passes to the monoarsenide. Chromium sesqui-arsenide is a grey powder, of density 6.2 at 22° C.; it is insoluble in acids.