Bismuth Phosphite, Bi₂(HPO₃)₃.3H₂O

Bismuth Phosphite, Bi₂(HPO₃)₃.3H₂O, is precipitated from a solution of ammonium phosphite by the addition of bismuth trichloride, by neutralising phosphorous acid with bismuth trioxide or hydroxide, or by the action of phosphorous acid upon an aqueous solution of bismuth nitrate and mannitol. The white needle-like crystals are only slightly soluble in water.