The Solubility of Octacalcium Phosphate at 37°C in the System Ca(OH)2-H 3PO4-KNO3-H2O

Abstract

The solubility product of octacalcium phosphate [Ca 4 H(PO 4 ) 3 · 2.5H 2 O] has been determined in the system Ca(OH) 2 -H 3 PO 4 KNO 3 -H 2 O at 37°C in experiments involving a range of hydrodynamics, ionic strength, and equilibration time. A value of pK so = 49.3 ± 0.2 was obtained for three different solid preparations by considering activity coefficients and ion-pair corrections.