Conclusions and Various Outlooks
The example evoked in this lecture demonstrate the advantages that can be derived from the concepts and methods of molecular quantum chemistry in order to explain crystal structure and to preict the shape of the crystals. Other possibilities, equally interesting, are offered by this theory. The above study is constructed on the prediction of the molecular orbitals that are used in the ground state. These orbitals are responsible for the cohesion of the system. They indicate the orbitals that do not participate (or only minimally) in the formation of the lattice and the orbitals that are not used. Knowledge of these orbitals permits one to obtain information on the electronic and magnetic properties. Our purpose is not to study this important set of properties. We shall only give same simple examples to show why the general description which we have given, can be used in these problems.