The novel (Cs4Nb6F8.5I3.5I6a)-I-1-I-1 octahedral niobium cluster fluoro-iodide: a step towards the Nb6F12i cluster core excision

摘要

The solid state synthesis of (Cs4Nb6F8.5I3.5I6a)-I-i-I-i starting from Nb6F15 binary fluoride, as well as its crystal structure determined by X-ray single crystal diffraction, are presented in this work. This novel cluster compound is based on a (Nb6I3F6L3I6a)-F-i-L-i-I-i (L = F, I) discrete unit and crystallizes in the monoclinic system (space group C2/m; Z = 4 ; a = 10.4363(4) Angstrom, b = 18.1227(7) Angstrom, c = 19.5102(9) Angstrom beta = 101.223(1)degrees, V = 3619.5(3) Angstrom(3)', R-1 = 0.057; wR(2) = 0.159). This halide is the first octahedral niobium cluster compound containing unshared terminal I-a ligands together with ordered mu(2)-I-i and mu(2)-F-i ligands on nine inner positions whilst the three last ones (L-i) are slightly affected by a I/F random occupancy. Tile structural findings are discussed and compared with those of Nb6F15, Nb6I11, CsNb6I11 and the fluorochlorides and fluorobromides recently reported. (C) 2003 Elsevier Inc. All rights reserved. [References: 25]