Heughebaert J C, Montel G
Calcif Tissue Int. 1982;34 Suppl 2:S103-8.
Precipitated calcium orthophosphate, rapidly prepared in highly supersaturated solutions at pH 9-11, is an amorphous tricalcium orthophosphate (atomic ratio Ca/P = 3/2) of formula Ca9(PO4)6, nH2O. Kept wet at room temperature, this phosphate is hydrolyzed according to the reaction PO4(3-) + H2O leads to HPO4(2-) + OH-; a tricalcium orthophosphate series is then formed, its general formula is Ca9 (HPO4)x (PO4)6-x (OH)x, O less than or equal to x less than or equal to 1. Moreover, the amorphous phosphate is converted into apatitic phosphate at half hydrolysis (x approximately equal to 0.5). The hydrolysis occurs simultaneously with an endothermic effect [delta H = 12.0 +/- 2.0 kJ/mol Ca9(PO4)6], and the conversion with an exothermic effect [delta H = -5.9 +/- 1.0 kJ/mol Ca9(PO4)6].
在pH值为9 - 11的高度过饱和溶液中快速制备的沉淀磷酸钙，是一种化学式为Ca9(PO4)6·nH2O的无定形磷酸三钙（钙/磷原子比 = 3/2）。在室温下保持湿润时，这种磷酸盐会根据反应PO4(3-) + H2O → HPO4(2-) + OH-发生水解；然后会形成一系列磷酸三钙，其通式为Ca9 (HPO4)x (PO4)6-x (OH)x，0 ≤ x ≤ 1。此外，无定形磷酸盐在水解一半时（x约等于0.5）会转化为磷灰石磷酸盐。水解与吸热效应[ΔH = 12.0 ± 2.0 kJ/mol Ca9(PO4)6]同时发生，而转化则与放热效应[ΔH = -5.9 ± 1.0 kJ/mol Ca9(PO4)6]同时发生。
