Model harmonic force fields of inorganic molecules and calculations of thermodynamic values of chemical compounds

Methodological foundations for selection of groups of inorganic compounds and ascertaining their force fields, which reguire monotonous variation of each force constant of the force fields of groups of molecules in coordinates Ki(ij)-NE(X), where Ki(ij)-force constant, NE(X)-the number of the central (E) or porifery (X) atom of molecules in a certain subgroup of the Periodic systems are explained. Numerous data on force constants and frequencies of normal vibrations of molecules formed by atoms of groups 3,4,6 and 7 of the Periodic system (halides and oxyhalides of B, Te, In, Mo, W, etc.) are presented