Low-Temperature Formation and Identification of Biphasic Calcium Carbonate Phosphates

• Published in: Russian journal of inorganic chemistry 2022-11, Vol.67 (11), p.1718-1730
• Main Authors: Glazov, I. E., Krut’ko, V. K., Musskaya, O. N., Kulak, A. I.
• Format: Article
• Language: English
• Subjects: Amorphization; Apatite; Calcite; Calcium carbonate; Calcium ions; Carbonation; Chemistry; Chemistry and Materials Science; Crystallization; Decantation; Hydroxyapatite; Inorganic Chemistry; Leaching; Low temperature; Phosphates; Synthesis and Properties of Inorganic Compounds; Thermal stability
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023622601313

Biphasic calcium carbonate phosphates comprised of amorphous calcium carbonate phosphate and carbonated hydroxyapatite were synthesized by wet precipitation at pH 9, Ca/P = 1.67, and concentrations of 0.60–0.90 mol/L under varying precipitation conditions. The wet formation of biphasic calcium carbonate phosphates includes a partial conversion of the amorphous phase into a mixture of carbonated hydroxyapatite and calcite, followed by leaching of calcite and constitutional Ca 2+ and ions during long-term decantation. The identification of biphasic calcium carbonate phosphates involves complex analysis using a spectroscopic method to elucidate carbonate substitution schemes, an X-ray diffraction method to determine the degree of apatite amorphization, and thermoanalytical methods to detect the effects of crystallization of the amorphous phase. Variations in the preparation parameters provide a means for controlling the contents of both amorphous calcium carbonate phosphate and constitutional ions in biphasic calcium carbonate phosphates, which amounts determine their resorbability and thermal stability.