Comparison of Model Systems (M+)n·[CrX63−] and M3CrX6+ 18MX Based on Quantum-Chemical Calculations (X: F, Cl)

Abstract

On the basis of quantum-chemical calculations the most stable particle compositions are estimated in such model systems as (M+)n·[CrCl6] and M3CrCl6+ 18MCl (M = Na, K, and Cs). In all systems these particles are positively charged. For systems (M+)n·[CrCl6], (M+)n·[CrF6], M3CrF6+ 18MCl, M3CrF6+ 18MF, and M3CrCl6+ 18MCl (M = Na, K, and Cs) a number of energy parameters characterizing the state of the system before and after electron transfer are calculated. The results indicate the possibility of electron transfer from the cathode to the melt system, which is in the initial state. However, this possibility cannot be realized in systems where LUMOs (lowest unoccupied molecular orbitals) have purely ligand character. In this case, the preliminary deformation of a cationic shell of electroactive species is required; it transforms the initial system to the transition state. However, in all considered systems the search of the transition state should be carried close to the initial statePi. This greatly simplifies a problem and transforms it from a purely theoretical sphere to the field of practical tasks that do not require exceptional cost of computer time.