A straightforward treatment of activity in aqueous CaCO3 solutions and the consequences for nucleation theory.

Kellermeier, Matthias; Picker, Andreas; Kempter, Andreas; Cölfen, Helmut; Gebauer, Denis · Adv Mater · 2014

basic_science · Level V

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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.