Halogenated sodium/lithium monocarba-closo-decaborates: syntheses, characterization, and solid-state ionic conductivity

A series of halogenated monocarba-closo-decaborates, M[closo-1-CHB9H8-6-X] (M = Na, Li; X = Br, I) and M[closo-1-CHB9H4-6,7,8,9,10-I5] (M = Na, Li) have been synthesized for systematically investigating the influence of halogenation of the monocarba-closo-decaborates on the thermal stability, phase transition and ionic conductivity. The thermal stability of halogenated derivatives is lower than that of the corresponding parent compounds of M[closo-1-CHB9H9] (M = Na, Li) with a trend of M[closo-1-CHB9H8-6-Br] M[closo-1-CHB9H8-6-I] > M[closo-1-CHB9H4-6,7,8,9,10-I5] (M = Na, Li). The results are supported by the theoretical calculation results based on ESP, suggesting that the ionic conductivities of halogenated derivatives are mainly influenced by anisotropic electron densities.