Uranous Arsenate, UH₂(AsO₄)₂

Uranous Arsenate, UH₂(AsO₄)₂.2H₂O, may be prepared by digesting freshly precipitated uranous hydroxide with cold dilute arsenic acid; or by adding arsenic acid to a solution of the hydroxide in sulphuric acid. It yields pale green needle-shaped crystals, insoluble in water but soluble in excess of arsenic acid. A tetrahydrate, UH₂(AsO₄)₂.4H₂O, is formed as a green precipitate when an alkali arsenate is added to a solution of a uranous salt.