The system CaCl2-(NH4)(2)HPO4-NH3-H2O-NH2CH2COOH was studied at 25 degrees
C by the solubility (residual concentrations) and pH measurement methods. T
he conditions leading to the precipitation of glycine-containing calcium hy
droxylapatite (glycinehydroxylapatite) were found. It is shown that the ani
onic form of glycine NH2CH2COO- isomorphically substitutes for part of the
OH- ions in the Ca channels of the hydroxylapatite lattice to form glycinea
patite Ca-10(PO4)(6)(OH)(2-x)(NH2CH2COO)(x). The x values grow from 0.07 to
0.4 with increasing glycine concentration of the starting solutions.