The first chlorofluoride in niobium cluster chemistry structure of the double salt: NaxF21-yCly (x ~ 2; y ~ 8)

The new compound NaxNb7 F21-yCly (x ~ 2 ; y ~ 8) synthesized by solid state chemistry crystallizes in the cubic system (space group Pm-3m) with a = 8.2005 (9) A. The structure has been determined by X-ray diffraction on single crystal ; it is related to that of Nb6F15. However, in the title compound, only one Nb6F 12F 6/2 subnetwork is preserved. The second one is replaced by (NbF6) entities. Additional Na cations provide the cohesion of the structure. We present here this new structure and discuss the possible oxidation states of the single niobium atom inside the (NbF6)n entities and the valency electron concentration (VEC) of the Nb6 cluster.