Molten salt synthesis and structural characterization of novel salt-inclusion vanadium bronze Cs5FeV5O13Cl6.

Single crystals of a new reduced vanadate phase, Cs(5)FeV(5)O(13)Cl(6), have been grown from the reaction of metal oxides V(2)O(5) and Fe(2)O(3) in the presence of a metal reducing agent in a eutectic CsCl/NaCl flux. This compound adopts a tetragonal structure (P4/nmm, a = 10.943(3) A, c = 10.535(4) A, Z = 2) that consists of reduced vanadate layers separated by ionic layers comprised of [FeCl(6)](3-) anions and Cs(+) cations. There are two distinct vanadium sites in the structure of this compound; V(4+) is in square pyramidal configuration, and V(5+) has a tetrahedral coordination environment. The (51)V NMR Knight shift and the magnetic susceptibility data indicate the delocalization of the unpaired electron of vanadium. Ferrimagnetic ordering is observed at 5 K.