COMPLICATED ISOMORPHISM IN SYNTHETIC CARBONATE-APATITES

摘要

Carbonate-bearing hydroxylapatites wereprepared by aqueous precipitation methods and byhydrothermal synthesis in wide range of conditions(temperature, alkalinity of me4ia, types of alkaline cations).From the point of their isomorphism, there have beendistinguished 5 groups of nonstoichiometric hydroxyapatitesdiffering in prevailing manner of the charge compensationwhile the substitution of P04 tetrahedra and OH groups by thecarbonate ion. It is shown that apatite of dental enamel turns tobe similar to the Ca-deficient alkaline-free carbonate apatitewith formula Ca_(10-x)(PO_4)_(6-x)(CO_3)_x(OH)_(2-x).