Transformation of Vaterite into Cubic Calcite in the Presence of Copper(II) Species

Abstract

By a simple washing of vaterite with ultrapure water, it transforms rapidly into cubic calcite. When the solid is washed with Cu 2+ solutions, the transformation depends on the concentrations of the copper solutions applied in the process. For concentrations of 10 - 4 mol dm - 3, a certain delay in the transformation process is detected, and the obtained cubic calcite seems to be in the form of Cu x Ca 1 - x CO 3 . For concentrations of 10 - 3 mol dm - 3, the vaterite structure remains stable with time, and this stability seems to be correlated with the saturation of the surface by Cu 2+ in place of Ca 2+ . For concentrations of 10 - 2 mol dm - 3, a mixture of vaterite, aragonite, cubic calcite, and malachite is obtained during the transformation process.