Rhodium Sulphate, Rh₂(SO₄)₃

Rhodium Sulphate, Rh₂(SO₄)₃, may be prepared by dissolving the sesquioxide in sulphuric acid, and evaporating the solution to a syrupy consistence over a flame, finally expelling the excess of sulphuric acid at a temperature not exceeding 440° C. Obtained in this way, rhodium sulphate is a brick-red powder, which is not hygroscopic. It is not very soluble in water, by excess of which it is decomposed. When heated to 500° C. it begins to decompose.