Compounds of Gold and Phosphorus

Phosphine reacts with a solution of auric chloride in anhydrous ether, forming auric phosphide, AuP, a substance decomposed by water or potassium-hydroxide solution, with formation of phosphine and phosphoric acid. At 100° to 110° C. it undergoes oxidation in the air. Heating in a current of carbon dioxide causes volatilization of phosphorus. Nitric acid oxidizes the phosphorus, leaving a residue of metallic gold. These reactions indicate the substance to be an alloy of gold and phosphorus.

Gold sesquiphosphide, Au₂P₃, is said to be formed by heating phosphorus with gold.

Another phosphide, Au₃P₄, is produced by the interaction of phosphorus vapour and gold. It is a grey, brittle substance, of density 6.67, and is formed only in the neighbourhood of 400° C. Acids react with it as with an alloy.