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• 作者：S. Cordier ; O. Hernandez ; J.-Y. Thé ; pot ; A. I. Shames ; and C. Perrin
• 刊名：Inorganic Chemistry
• 出版年：2003
• 出版时间：February 24, 2003
• 年：2003
• 卷：42
• 期：4
• 页码：1101 - 1106
• 全文大小：196K
• 年卷期：v.42,no.4(February 24, 2003)
• ISSN：1520-510X

文摘

The synthesis and the crystal structure of the first compound containing Nb₃ triangular clusters bonded to fluorineligands are presented in this work. The structure of Nb₃IF₇L(NbL₂)_0.25 with L = O and F, determined by single-crystal X-ray diffraction, is based on a Nb₃IⁱFⁱ₃F^a₈L^a unit and a NbL₆ octahedron (tetragonal, space group I4/m, a= 13.8638(3) Å, c = 8.9183(2) Å, V = 1714.14(7) ų, Z = 8). Two crystallographic positions (noted L5 and L6)are randomly occupied by fluorine and oxygen with two different F:O occupancies. These L ligands build an octahedralsite for a single niobium atom, located between the units. The four L5 ligands of the NbL₆ octahedron are sharedwith four Nb₃ cluster units, while the two other L6 ligands are terminal. The Nb₃ cluster is face-capped by oneiodine and edge-bridged by three fluorine ligands. Two of the three niobium atoms constituting the cluster arebonded to three additional apical fluorine ligands, while the third one is bonded to two fluorines and one L5 ligand.The Nb₃ cluster is linked to six adjacent ones via all the apical fluorine ligands. The developed formula of the unitis therefore Nb₃IⁱFⁱ₃F^a-a_8/2L^a according to the Schäfer and Schnering notation. The oxidation state of the singleniobium and the random distribution of fluorine and oxygen on the two L sites will be discussed on the basis ofstructural analysis, the bond valence method, and IR and EPR measurements. The structural results will be comparedto those of previously reported niobium compounds containing NbF₆ or Nb(F,O)₆ octahedra.