Thallic hydrogen oxalate, TlH(C₂O₄)₂

Thallic hydrogen oxalate, TlH(C₂O₄)₂.3H₂O, is readily obtained as a white, sparingly soluble, crystalline powder, by the action of aqueous oxalic acid at 25° on thallic hydroxide or an acetic acid solution of thallic acetate. The corresponding potassium and ammonium salts may be obtained by precipitating acid solutions of thallic salts with potassium and ammonium oxalate respectively.