The Existence of Pure‐Phase Transition Metal Hydroxy Apatites

The existence of pure‐phase transition metal hydroxy apatites of zinc, copper, manganese, and cobalt could not be verified by repeated attempts to duplicate the few literature procedures reported for their preparation in aqueous solution. Variations of temperature, time of reactions, pH, and use of decomplexation also did not produce apatitic compounds. In the case of zinc, the product resulting from the addition of zinc nitrate to ammonium dihydrogen phosphate in solutions brought to pH >9 with ammonia appears to be a zinc ammonia complex with phosphate as the counter ion. Extensive drying removed ammonia to produce the phosphate. At pH