David R. Slim

A new cationic S–N ring system, S4N42+. The crystal structure of cyclotetrathiazyl bis hexachloroantimonate(V), [S4N4][SbCl6]2, and cyclotetrathiazyl hexafluoroantimonate(V) tetradecafluorotriantimonate, [S4N4][SbF6][Sb3F14]

An X-ray crystallographic study has shown that the new cyclic cation S4N42+ has different structures in the compounds [S4N4][SbCl6]2 and [S4N4][SbF6][Sb3F14] which were prepared by the reactions of S4N4 or S3N3Cl3 with SbCl5 and of S4N4 with SbF5, respectively.

Fluoride crystal structures. Part 33. Tetraethylammonium µ-fluoro-bis[oxoperoxo(pyridine-2,6-dicarboxylato)molybdate(VI)]

The structure of the title compound has been determined by the heavy-atom method from 2 417 reflections, measured with a diffractometer, and refined by full-matrix least-squares methods to R.0.044. Crystals are monoclinic, space group C2/c, with unit cell dimensions a= 18.55(2), b= 12.43(2), c= 14.17(2)A, and β= 119.1(3)°. In the structure each molybdenum atom has a pentagonal-bipyramidal co-ordination, with the centrosymmetric binuclear anions formed by axially linking two units, through a symmetric fluorine bridge. The Mo–F distance of 2.135 A is very long, due to the trans effect of the oxide ligand (Mo–O 1.659 A) and to the bridging role of the fluorine atom.

X-Ray crystal structure of Te6(AsF6)4·2AsF3. A new trigonalprismatic cluster cation Te64+

A single cyrstal X-ray diffraction study has shown that Te6(AsF6)4·2AsF3 contains the novel trigonal primatic cluster Te64+.

Fluoride crystal structures. Part 30. 2,2′-Bipyridylfluorodioxovanadium(V)

The structure of the title compound has been determined from X-ray diffractometer data and refined by full-matrix least-squares methods to R 0.078 for 1 084 reflections. Crystals are monoclinic, space group P21/c, a= 6.43, b= 15.80, c= 13.94 A, β= 134.8°. The vanadium atom has a distorted square pyramidal arrangement and achieves a distorted octahedral co-ordination by weak dimer formation, through asymmetric oxygen bridges. The vanadium–oxygen distances are V–O (terminal) 1.618(8) and V–O (bridge) 1.691(7) and 2.361(7)A.

Preparation of antimony(V) trichloride difluoride and its characterization by means of X-ray crystallography, antimony-121 Mössbauer, and Raman spectroscopy

Antimony trichloride difluoride has been prepared by the reaction of SbCl4F and SbF5 in liquid SO2 and has been characterized by single-crystal X-ray diffraction studies and by Raman and Mossbauer spectroscopy. Crystals are tetragonal with a= 12.81(1), c= 7.282(7)A, U= 1 194.6 A3, Z= 8, and Dc= 2.96 g cm–3. The structure has been refined in the space group /4 to a conventional R′ index 0.073 for 265 independent reflections. The structure consists of cis-fluorine-bridged tetramers with each antimony having a distorted octahedral arrangement of three chlorines and three fluorines.

Crystal structure of (IOF3·IO2F3)2

The crystal structure of (IOF3·IO2F3)2 has been determined from three-dimensional X-ray counter data at -45 °C. Crystals are monoclinic with a= 9.832(4), b= 8.307(5), c= 10.187(7)A, β= 125.46(7)°, U= 677.7 A3, Z= 4, and Dc= 4.08 g cm–3. The structure has been refined in the space group P21/n to a final conventional R′ index of 0.061 for 1 289 independent reflections. It consists of two IOF2 and two IO2F4 units linked by asymmetric oxygen bridges to give a cyclic molecule. These molecules are weakly bounded together in sheets by additional weak oxygen bridges.

Crystal structure of µ-fluorosulphato-bis[fluoroxenon(II)] hexafluoroarsenate(V)

The crystal structure of [(XeF)2SFO3][AsF6] has been determined from three-dimensional X-ray counter data. Crystals are monoclinic with a= 11.178(5), b= 8.718(5), c= 11.687(6)A, β= 91.28(4)°, U= 1 132 A3, Z= 4, and Dc= 3.45 g cm–3. The structure has been refined in the space group P21/n to a final conventional R′ of 0.87 for 1 147 independent reflections. The structure consists of discrete [(XeF)2SFO3][AsF6] units with no cation–anion contact less than 3.0 A. The cation consists of a nearly tetrahedral fluorosulphate group having a Xe–O bond to each Xe–F group. The two linear F–Xe–O groups are slightly staggered with respect to each other.

The crystal structure of the 1 : 1 adduct of antimony trifluoride and antimony pentafluoride

A single-crystal X-ray diffraction study of the compound (SbF4)4 shows that it is monoclinic with the following unit-cell dimensions: a= 9.32(1), b= 12.07(1), c= 11.60(1)A, β= 107.1(3)°, space group P21/c, and Z= 4. Refinement by full-matrix least-squares methods of all parameters with anisotroptc temperature factors on the heavy atoms gave an R of 0.071 for 2 048 observed reflections. The asymmetric unit consists of an [Sb2F4]2+ cation and two [SbF6]– anions. When the longer SbIII–F contacts are considered then the structure must be described as an infinite three-dimensional polymer.

Fluoride crystal structures. Part 31. Ammonium fluoro-oxoperoxo-(pyridine-2,6-dicarboxylato)molybdate(VI)

The structure of the title compound has been determined by the heavy-atom method from 1 350 reflections, measured with a diffractometer, and refined by full-matrix least-squares methods to R 0.046. Crystal are orthorhombic, space group Pbca, with a= 11.15(2), b= 26.25(4), and c= 7.56(1)A. In the structure the monomeric anions have a pentagonal-bipyramidal co-ordination, with the bidentate peroxo-group and terdentate pyridine-2,6-di-carboxylate group filling the equatorial positions, and the oxide and fluoride ligands in the axial positions. There is a very long MO–F distance (2.058 A), which can be correlated with the trans effect of the oxide ligand (MO–O 1.661 A).

The crystal structure of trifluoroxenon(IV) hexafluorobismuthate(V): the fluoride-acceptor strength of bismuth pentafluoride

The crystal structure of [XeF3][BiF6] has been determined from three-dimensional X-ray counter data. Crystals are triclinic with a= 5.698(3), b= 7.811(3), c= 8.854(4)A, α= 99.45(5), β= 110.09(5), γ= 92.84(5)°, U= 362.7 A3, Z= 2, and Dc= 4.69 g cm–3. The structure has been refined in the space group P to a final conventional R′ of 0.097 for 1 238 independent reflections. The structure consists of [XeF3]+ and [BiF6]– ions with a close contact of 2.25(2)A between the xenon atom of the T-shaped cation and fluorine atom of the octahedral anion. The bridging fluorine is shown to be more strongly associated with the xenon in [XeF3][BiF6] than in [XeF3][SbF6], indicating that BiF5 is a weaker fluoride acceptor than SbF5.