Ceric dihydrogen arsenate, Ce(H₂AsO₄)₄

Ceric dihydrogen arsenate, Ce(H₂AsO₄)₄.4H₂O, may be prepared by heating cerous nitrate (1 mol.) and arsenic acid (4 mols.) with concentrated nitric acid for several hours, distilling off most of the nitric acid, and allowing the liquid to crystallise. The salt separates in white needles. When it is dissolved in the minimum quantity of concentrated nitric acid and the cold solution diluted with water, a white, crystalline precipitate of ceric monohydrogen arsenate, Ce(HAsO₄)₂.6H₂O, is obtained.