Uranyl Phosphite, (UO₂)₃H₆(PO₃)₄

Uranyl Phosphite, (UO₂)₃H₆(PO₃)₄.12H₂O, is precipitated on the addition of ammonium diuranate to an aqueous solution of phosphorus trichloride. On drying in the air it becomes hard and transparent; over sulphuric acid it loses 7 molecules of water. On heating, it loses two-thirds of its water at 180° C., and becomes anhydrous, at the same time turning green, at 300° C.