Anisotropic surface properties of calcite: A consideration of surface broken bonds.

The anisotropic physicochemical properties of calcite, including cleavage nature, surface (free) energy, surface relaxation degree, wettability and adsorption behaviour, were revisited in this paper based on the surface structures and surface broken bonds reported previously. The relationships between these surface properties were also discussed. The analysis indicated that the positive relationship between the density of surface broken bonds and the surface energy of calcite was established, and the former could be used to predict the cleavage nature, commonly exposed surfaces and the degree of surface relaxation. The distribution characteristic and the number of broken (or unsaturated) bonds of surface Ca atoms can be used to explain the anisotropic surface wetting and adsorption behaviour of calcite. This review demonstrated that surface broken bonds could be a fast way to study the surface properties of minerals and materials. [ABSTRACT FROM AUTHOR]