Thermochemistry of organic, heteroorganic and inorganic species. XV. The enthalpies of formation for halogenides of main group elements

Systematization of known experimental and theoretical data on the enthalpies of formation for halogenides of main group elements has been performed. Applying the enthalpic shift procedure, the definite trends in the enthalpy of formation/structure interrelationships have been found and these are interpreted as interplay of polarizability and electronegativity effects. These formulated trends permit to find out many unknown values and to suggest reasonable ones in case of known but conflicting cases for full halogenides and especially for hydrogenated halogenides. The data on about 150 unknown species are presented. It was shown that all full elements's halogenides are thermodynamically stable in relation to their decomposition on fragments while among 322 hydrides and H-comprising halogenides only 24 appeared to be thermodynamically unstable relative to their fragmentation to lower valency products. However, nearly all the latter might be stable kinetically. The effect of σ-conjugation (anomeric effect) in stabilization of halogenides of IV and V-group of elements is called in question.