Auric sulphate, Au₂(SO₄)₃

The Auric sulphate, Au₂(SO₄)₃ has not been isolated. Gold dissolves in concentrated sulphuric acid in presence of a small proportion of nitric acid, forming a yellow liquid, but dilution reprecipitates the gold, either as the hydroxide, or in presence of reducers as the metal. The nitric acid can be replaced by other oxidizers, such as iodic acid and manganese dioxide; and a solution of the sulphate is also formed by the action of concentrated sulphuric acid on auric oxide.