A Straightforward Treatment of Activity in Aqueous CaCO₃ Solutions and the Consequences for Nucleation Theory

Abstract

The aqueous calcium carbonate system is rigorously investigated with respect to ionic activity. Ideal treatment is found to be a good approximation at relevant concentrations. The data further show that bound CaCO3 species cannot be regarded as "inactive" during nucleation but rather appear to play a key role in the phase-separation process, and that amorphous calcium carbonate (ACC) can be precipitated from much lower levels of supersaturation than previously believed.