Dinuclear oxofluorometallates as a new structural type of d(0) transition metal oxofluoride compound.

Five isomorphous d(0) transition metal oxofluoride compounds A(3)[M(2)O(x)F(11-x)]·(AF)(0.333) (A = K, Rb, NH(4); M = Nb, Mo, W; x = 2, 4) have been synthesized from acid fluoride solutions, and their crystal structures have been determined by single-crystal X-ray diffraction. The basic structural building units are dinuclear M(2)X(11) (dimers) formed from NbOF(5) or Mo(W)O(2)F(4) octahedra connected by the fluorine bridging atom. In the Nb(2)O(2)F(9) dimer, the O atoms occupy apical corners. In the M(2)O(4)F(7) (M = Mo, W) dimers two O atoms are also apically placed, whereas the other two O atoms are statistically disordered in equatorial planes. The arrangement of dimers is so that the hexagonal tunnels containing `free' fluoride ions are formed. During the irradiation process the orthorhombic structure of K(3)Nb(2)O(2)F(9)·(KF)(0.333) transforms into a pseudo-trigonal one with a = 23.15 Å, which is the [101] diagonal of the orthorhombic unit cell. The other four trigonal crystals are merohedral twins.

[1]  C. Stern,et al.  New Layered Oxide-Fluoride Perovskites: KNaNbOF5 and KNaMO2F4 (M = Mo6+, W6+) , 2011 .

[2]  M. A. Fedotov,et al.  Hydrolysis of ammonium oxofluorotungstates: A 19F, 17O and 183W NMR study , 2010 .

[3]  C. Stern,et al.  Chemical Hardness and the Adaptive Coordination Behavior of the d0 Transition Metal Oxide Fluoride Anions , 2009 .

[4]  C. Stern,et al.  Cation-anion interactions and polar structures in the solid state. , 2007, Journal of the American Chemical Society.

[5]  D. Dixon,et al.  Lewis Acid Behavior of ReO2F3: Synthesis of (ReO2F3)∞, ReO2F4-, Re2O4F7-, Re3O6F10-, and ReO2F3(CH3CN) and Study by NMR Spectroscopy, Raman Spectroscopy, and Density Functional Theory Calculations; and X-ray Structures of [Li][ReO2F4], [K][Re2O4F7], [K][Re2O4F7]·2ReO2F3, [Cs][Re3O6F10], and ReO3F(CH , 1999 .

[6]  A. Linden,et al.  Controlled hydrolysis of the hexafluorides of molybdenum, tungsten and rhenium: structure of oxonium (.mu.-fluoro)bis(tetrafluorooxotungstate(VI)) , 1987 .

[7]  R. Mattes,et al.  Structure and properties of the fluorine-rich oxofluoromolybdates Cs3[Mo2O6F3], (NH4)3[Mo2O2F9] and (NH4)2[MoOF5] , 1980 .

[8]  G. Sheldrick.  A short history of SHELX. , 2008, Acta crystallographica. Section A, Foundations of crystallography.

[9]  D. Dixon,et al.  Lewis-Acid Properties of Technetium(VII) Dioxide Trifluoride, TcO2F3: Characterization by 19F, 17O, and 99Tc NMR Spectroscopy and Raman Spectroscopy, Density Functional Theory Calculations of TcO2F3, M+TcO2F4- [M = Li, Cs, N(CH3)4], and TcO2F3·CH3CN, and X-ray Crystal Structure of Li+TcO2F4- † , 1998 .

[10]  J. M. Winfield,et al.  Magnetic double-resonance study of some derivatives of tungsten hexafluoride and tungsten oxotetrafluoride , 1971 .