Dependence of the values of calcite and aragonite thermodynamic solubility products on ionic models.

Abstract

In view of the fact that interpretation of the behaviour of calcite and aragonite in natural waters requires accurate determination of the dynamic solubility products (Ksp) of the minerals, the influence of experimental methods and ionic activity models was investigated. The results demonstrate the need to use activity coefficients based on the ion-pairing model and gave values of pKsp = 8.48 + or - 0.02 and pKsp = 8.30 + or - 0.02 for calcite and aragonite, respectively, at 25oC. -M.S.