Acid Calcium Hypophosphate, CaH2P2O6, may be prepared by mixing freshly precipitated lime and hypophosphoric acid in exactly equivalent proportions and evaporating in the cold. Heating the solution gives the neutral salt. A solution of the acid salt may also be obtained by dissolving the neutral salt in hypophosphoric acid, or by digesting with water a mixture of acid barium hypophosphate and calcium sulphate in molecular proportions.
It forms monoclinic crystals of composition CaH2P2O6.6H2O, which easily lose 4 molecules of water at the ordinary temperature. The remaining two are removed at 150° C. with partial decomposition. One part of the salt dissolves in 60 of water. |