ABSTRACT

This chapter deals with a discussion of thermodynamic speciation models and the classical theories of nucleation and spinodal decomposition in contrast to the recently asserted prenucleation cluster theory that is challenging them. The intricate skeletal structures that are formed as the products of controlled biomineralization have long-fascinated researchers and inspired scientific inquiries. The classical nucleation theory provides a means of describing the free energy landscape upon which the nascent clusters grow into the bulk phase. The global energy minimum corresponds to the Ca–C distance where the carbonate ion complexes calcium as a monodentate contact ion pair (CIP). The local minimum at a somewhat shorter separation distance represents the bidentate CIP. The common objective of almost all of the studies is to determine which phase of CaCO3 is thermodynamically preferred at a given nanoparticle size.