TRANSFORMATION OF VATERITE INTO CUBIC CALCITE IN THE PRESENCE OF COPPER(II) SPECIES

By a simple washing of vaterite with ultrapure water, it transforms ra pidly into cubic calcite. When the solid is washed with Cu2+ solutions , the transformation depends on the concentrations of the copper solut ions applied in the process. For concentrations of 10(-4) mol dm(-3), a certain delay in the transformation process is detected, and the obt ained cubic calcite seems to be in the form of CuxCa1-xCO3. For concen trations of 10(-3) mol dm(-3), the vaterite structure remains stable w ith time, and this stability seems to be correlated with the saturatio n of the surface by Cu2+ in place of Ca2+. For concentrations of 10(-2 ) mol dm(-3) a mixture of vaterite, aragonite, cubic calcite, and mala chite is obtained during the transformation process.