Preparation and characterization of cadmium–calcium hydroxyapatite solid solution particles

Cadmium–calcium hydroxyapatite (CdCaHap) solid solutions with different atomic ratios Cd/(Cd + Ca) (XCd) of 0–1 were synthesized by a wet method and characterized by various means. XCd of all the obtained solid solution particles was slightly larger than Cd/(Cd + Ca) atomic ratio in the starting solutions ([XCd]), that is, Cd2+ ions were a little more easily incorporated into hydroxyapatite (Hap) crystals compared to Ca2+ ions. With increasing Cd2+ content, the unit cell dimensions a and c decreased, the particles became large spherical agglomerates, and the specific surface area decreased. The amount of CO2 irreversibly adsorbed on CdCaHap was lower on average than those on the other Hap particles.