Madelung Parameters and Electrostatic Energies for Calcite, Aragonite, and Vaterite and the Charge Distribution on the Carbonate Ion

The electrostatic energy changes and Madelung parameters for the process CaCo3(c)→Ca2+(g)+CO32−(g)have been computed assigning various distributed charges to the CO32- ion for the calcite, aragonite, and vaterite forms of calcium carbonate. The results are expressed as quadratic one-parameter functions, A+BQ(O)+CQ(O)2, of the charge Q(O) placed on the oxygen atom of the CO32- ion. A comparison with previous calculations is made and the charge distribution and quadrupole moment of the CO32- ion estimated.