Browsing by Author "Hoelzel, Markus"

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  • The Crystal Structures of α- and β-F 2 Revisited
    (2019-01-01) Ivlev, Sergei I.; Karttunen, Antti J.; Hoelzel, Markus; Conrad, Matthias; Kraus, Florian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The crystal structures of α-F 2 and β-F 2 have been reinvestigated using neutron powder diffraction. For the low-temperature phase α-F 2 , which is stable below circa 45.6 K, the monoclinic space group C2/c with lattice parameters a=5.4780(12), b=3.2701(7), c=7.2651(17) Å, β=102.088(18)°, V=127.26(5) Å 3 , mS8, Z=4 at 10 K can now be confirmed. The structure model was significantly improved, allowed for the anisotropic refinement of the F atom, and an F−F bond length of 1.404(12) Å was obtained, which is in excellent agreement with spectroscopic data and high-level quantum chemical predictions. The high-temperature phase β-F 2 , stable between circa 45.6 K and the melting point of 53.53 K, crystallizes in the cubic primitive space group Pm (Formula presented.) n with the lattice parameter a=6.5314(15) Å, V=278.62(11) Å 3 , cP16, Z=8, at 48 K. β-F 2 is isotypic to γ-O 2 and δ-N 2 . The centres of gravity of the F 2 molecules are arranged like the atoms in the Cr 3 Si structure type.
  • Crystal Structures of α- And β-Nitrogen Trifluoride
    (2019-05-06) Ivlev, Sergei I.; Conrad, Matthias; Hoelzel, Markus; Karttunen, Antti J.; Kraus, Florian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The crystal structures of α-NF 3 and β-NF 3 are reported for the first time. As shown by powder neutron diffraction, the lowerature α-NF 3 crystallizes in the orthorhombic space group Pnma (oP16) with lattice parameters a = 6.71457(13) Å, b = 7.30913(14) Å, c = 4.55189(8) Å, V = 223.396(7) Å 3 , and Z = 4 at T = 6 K. The intramolecular atom distances in α-NF 3 are 1.3639(16) and 1.3677(11) Å for N-F, and 2.1216(16) and 2.120(2) Å for F···F. The F-N-F bond angles are 101.92(7)° and 101.63(10)°. All data are in excellent agreement with quantum-chemical predictions and previously reported experimentally obtained gas-phase data. The higherature β-NF 3 is a plastic crystal, space group P4 2 /mnm (tP120), with the lattice parameters a = 15.334(6) Å, c = 7.820(3) Å, V = 1838.6(12) Å 3 , and Z = 30 at T = 60 K. Its crystal structure is closely related to that of the Frank-Kasper sigma phase.
  • A Neutron Diffraction and Quantum-Chemical Study of [Mn(ND3)6](N3)2
    (2018-06-11) Ivlev, Sergei I.; Müller, Thomas G.; Karttunen, Antti J.; Hoelzel, Markus; Kraus, Florian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    [Mn(ND3)6](N3)2 was obtained by careful decomposition of [Mn(ND3)6](N3)2·4ND3 at room temperature. It crystallizes in the monoclinic space group I2/m with a = 8.5905(5), b = 6.8506(4), c = 9.7530(6) Å, β = 94.618(6)°, V = 572.10(6) Å3, Z = 2, at T = 3 K. Its crystal structure was elucidated using powder neutron diffraction and confirmed by quantum chemical calculations. The MnII cation is coordinated octrahedron-like by ND3 ligands. The azide anion is linear with 178.7(10)° and shows N-N distances of 1.178(11) and 1.180(12) Å.
  • Synthesis and Characterization of Barium Tetrafluoridobromate(III) Ba(BrF4)2
    (2014) Ivlev, Sergey; Sobolev, Vasily; Hoelzel, Markus; Karttunen, Antti J.; Müller, Thomas; Gerin, Ivan; Ostvald, Roman; Kraus, Florian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä