Interionic forces and ionic polarization in alkaline earth halide crystals

Ionic force parameters for a soft sphere model have been derived from the known crystal structures and thermodynamic lattice energies of alkaline earth halides. Polarization of the chloride, bromide, and iodide ions has been taken into account by a simple shell-core model. The derived parameters are capable of reproducing the crystal structures of the alkaline earth halides to within a root mean square deviation of under 3% in interionic distance. Ionic polarizabilities are in rough agreement with those deduced for crystal ion polarizabilities by other means but are smaller than the commonly accepted values in all cases.