Acid auryl sulphate, AuOHSO₄

Acid auryl sulphate, AuOHSO₄, is produced by the action of concentrated sulphuric acid on auric hydroxide at 180° C., the brown, basic salt formed being converted by heating at 200° C. into the yellow acid auryl sulphate. It is decomposed by water with formation of auric hydroxide, but dissolves in concentrated sulphuric acid to a yellowish-red solution, from which it separates unchanged. When this acid solution is heated with potassium hydrogen sulphate, a yellow, crystalline salt of the formula KAu(SO₄)₂ separates. It is more stable than acid auryl sulphate, but is slowly decomposed by water, with formation of auric hydroxide, potassium sulphate, and sulphuric acid. A silver salt of similar type has also been prepared.