| Ammonium ferri-diorthophosphate, NH4.H2[Fe(PO4)2], was first obtained by Danziger by addition of a large excess of di-ammonium hydrogen phosphate to a strongly acid solution of ferric chloride. It is then formed as a white precipitate. If obtained in an analogous manner to the preceding salt, it yields pink, microscopic, hexagonal crystals. In the absence of a sufficient quantity of ammonia the acid salt, [Fe(PO4)2.H2]NH3.7H2O, is obtained. |