Relationship between the valence electron theory and the electron density theory in crystal

The valence electron theory and the electron density theory can be connected in terms of the atomic action volume. The nonspherical symmetry of the electronic cloud is emphasized in the valence electron theory and the spherical symmetry of the electronic cloud is supposed in the electron density theory. The basic parameters in the valence electron theory are the bond length and the amount of valence electron; while the basic parameters in the electron density theory are the atomic radius and the electron density. Generally, experimental results are used in both theories to determine the value of the bond length and the atomic radius, but the amount of the valence electron and the electron density should be given according to specific theory or model. In these theories, only one parameter can be calculated, namely, either the amount of valence electron in the valence electron theory or the electron density in the electron density theory. These two parameters can he related by means of the action volume of the atoms, so that, one parameter can be calculated from the other.