Energy Additivity in Glasses *

A bstract Energies of dissociation into the component ions have been computed for many simple and complex oxides. From these, 51 energy constants have been obtained, which may be used to compute approximate ionic dissociation energies in crystals and glasses in which each “metallic” atom is surrounded by oxygens. The relation of these constants to the Periodic Table is shown and briefly discussed. Slight deviations from additivity in silicates and phosphates are related to the dependence of the energy on the number of oxygens in SiO 4 and PO 4 groups which are shared with other & or P atoms.