COMPRESSIBILITY AND POLYMORPHISM OF SOLIDS.

The compressibility of solids is expressed in terms of fundamental physical quantities in relation to the energy of an electron in the L-shell orbital. When the concept of apparent valency z sub a rhoz, the product of classical valency z and the ratio rho of the atomic coordinations of two successive polymorphs is used, the formula becomes generally applicable. As a result, the structure of each substance under ambient conditions can be classified as being either in the reduced, basic or elevated state. This allows the prediction of volumetric compressibility data from pertinent atomic data and physical constants as well as a qualitative prediction of possible structural modifications. The relationship between the damping parameter of a solid and the radius ratio is shown to be useful in differentiating between the various possible structural modifications under a given set of pressure and temperature conditions. Author