An unusual hybrid fluoride featuring a [V7F27]6− chain motif based on a pyrochlore-like building unit

A new hybrid vanadium (III) fluoride [C4H12N2]3[V7F27] has been synthesised solvothermally. The crystal structure (trigonal, R3¯c; a=17.367(2) Å, c=19.604(2) Å) reveals an unusual and novel chain motif consisting of pyrochlore-like heptameric units of corner-sharing octahedra, which are further linked into linear chains of alternating triple and single octahedral groups. The chains are separated by hydrogen-bonded piperazinium moieties. Magnetic susceptibility data show moderate antiferromagnetic interactions but no long-range order above 2 K, consistent with pronounced one-dimensional character, as well as frustration arising within the triangular units of magnetic ions in the chains.