title: 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.
authors.affiliation: Physical Chemistry, University of Konstanz, D-78464, Konstanz, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kellermeier
authors.forename: Andreas
authors.initials: A
authors.lastname: Picker
authors.forename: Andreas
authors.initials: A
authors.lastname: Kempter
authors.forename: Helmut
authors.initials: H
authors.lastname: Cölfen
authors.forename: Denis
authors.initials: D
authors.lastname: Gebauer
keywords: activity; calcium carbonate; crystallization; electrolytes; nucleation