Phase transitions and formation of polytypes in crystal structures of ionic compounds

In the present investigation a new approach for a d esign of system of chemical bonds in crystals – geo metric conception of chemical bond (GCCB) – has been used. In GCCB the term “chemical bond”, the shape of the atoms and the relative dimensions of the valence or bitals of the atoms are strictly determined in initial postulates that allow to obtain a full collection of all possible valence configurations of the atoms. The configurations of excited atoms are used as the ele m nts for design of crystal structures. Models of s ystems of chemical bonds in basic structural types of ionic c ompounds have been created.