Silver alum, Ag₂SO₄.Al₂(SO₄)₃

Silver alum, Ag₂SO₄.Al₂(SO₄)₃.24H₂O, is said to be prepared by heating silver sulphate and aluminium sulphate, together with a little water, in a sealed tube, and allowing the solution to cool. The existence of this alum is denied by Retgers.