Gold Arsenides

Alloys containing up to 25 atoms per cent, of arsenic have been prepared by fusing together gold and an alloy rich in arsenic. The freezing point curve reveals a eutectic point at 665° C. with about 46 atoms As per cent. Several arsenides have been described. Descamps, by adding metallic arsenic to a solution of auric chloride, obtained a dark red deposit somewhat richer in arsenic than corresponds to the composition Au₃As. This product when fused with potassium cyanide is converted into a yellow arsenide, Au₄As₃, of density 16.2. The monarsenide, AuAs, was prepared by Brukl by dropping a solution of sodium chloraurate into an atmosphere of arsine. This arsenide is stable towards dilute acids and alkalis. Concentrated nitric acid reduces it to spongy gold. At high temperatures it decomposes with almost complete loss of arsenic.