Ab Initio Estimation of NbF− 6 , NbClF2− 6 , and NbF2− 7 Complexes Stability in Alkali Chloride Melts

Abstract

Quantum-chemical calculations of the parameters of the nM+ ・NbClF2− 6 type particles have been performed, where M stands for Na, K, Cs and n = 0 - 6. Under certain conditions such particles may exist in melts of alkali metal chlorides.Within the framework of this approximation, compositions for themost stable particles in molten salts were obtained. Relative stability of the particles containing the NbF − 6 , NbClF2− 6 , and NbF2− 7 complexes has been calculated. Energies and some other characteristics of the electron structure and the particle geometry structure were determined depending on the n and M values. For estimation of the third sphere’s influence, the systems (M2NbF7 +8MCl) and (M2NbF7 +15MCl) are surveyed. The chlorine anion enters the first coordination sphere in the Nasystem only, i. e. in this system the true complex NbClF3− 7 is formed.