Thermodynamic arguments based on crystalline structures have, in the past, proved equally valuable to arguments based on optical basicity for dealing with many features of glasses & glass melts. A link has previously been established between optical basicity & thermo-chemistry, & since optical basicity can be obtained from refractive index & density, there is motivation for exploring possible relationships between thermochemistry & refractivity data. Calculations are made for various crystalline metal silicates to obtain: values of lattice energies/oxygen atom &, oxide polarisabilities from refractive index & density. When these are plotted against each other, it is found that the points follow a smooth trend which passes through points for the binary oxides SrO, CaO & SiO2.
