Introduction

Abstract

The problem of the development of new materials with specified properties can be approached in several basically different ways. One is the analysis of the accumulated experimental data and the derivation of the relationships between various properties from these data. A different approach consists of the extrapolation of the properties of well-known materials to those which have not yet been studied but which belong to the same class or type and have identical or similar crystal structures. These two ways and similar ones are based on the known experimental information and involve a “reorganization” of such information without answering the question as to why a particular material has these and not other properties, why it is a refractory, why it has this and not some other specific heat, and generally, why it behaves in this way and not another. Obviously, answers to all these questions can be obtained only if we know the functional relationships betweenthe electron structure and the properties of the material. Such relationships can be deduced from suitable concepts relating to the structure of matter, which must be based on the electron structure of atoms and which demonstrate the direct relationship between this structure and the macroscopic properties.