03 Fakultät Chemie

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/4

Browse

Author: search.filters.author.Strobel, SabineSubject: search.filters.subject.540

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    New crystal structures of rare‐earth metal(III) oxotellurates(IV) RE2Te3O9: A1‐type (RE=La, Ce) and A2‐type (RE=Pr, Nd)
    (2021) Chou, Sheng‐Chun; Höss, Patrick; Russ, Philip L.; Strobel, Sabine; Schleid, Thomas
    The new rare-earth metal(III) oxotellurates(IV) RE2Te3O9 (RE=La-Nd) of the so far unknown A-type structure can be obtained as needle-shaped single crystals through solid-state reactions of the corresponding binary oxides. Their crystal structures were determined as A1-type for RE=La and Ce or A2-type for RE=Pr and Nd by single-crystal X-ray diffraction. Both structure types crystallize in the monoclinic crystal system, but in two different non-centrosymmetric space groups: the A1-type with Z=8 in space group P21 (La2Te3O9: a=569.54(3), b=2230.12(13), c=1464.71(4) pm, β=101.205(3)°; Ce2Te3O9: a=567.02(3), b=2222.61(13), c=1457.13(9) pm, β=101.134(3)°) or the A2-type with Z=16 in space group Cc (Pr2Te3O9: a=2838.61(16), b=563.89(3), c=2522.08(15) pm, β=118.816(3)°; Nd2Te3O9: a=2826.38(16), b=561.47(3), c=2511.94(15) pm, β=118.841(3)°). In spite of the differences in the unit-cell parameters and the symmetry, both structures consist of quite similar fundamental building blocks (FBBs) consisting of eight crystallographically distinct rare-earth metal-oxygen polyhedra with C.N.(RE3+) from seven to nine and always twelve different ψ1-tetrahedral oxotellurate(IV) anions [TeO3]2-, which show a high number of secondary bonding interactions (SBIs) with each other in all four cases.
  • Thumbnail Image
    ItemOpen Access
    Two of a kind : the cerium(III) oxidomolybdates(VI) Ce2Mo3O12 and Ce4Mo7O27
    (2025) Knies, Benjamin; Strobel, Sabine; Hartenbach, Ingo
    Although primarily received as by‐products, the title compounds can be synthesized directly by the admixture of CeO2, Ce, and MoO3, with the latter used as reactant and fluxing agent in flux‐mediated solid‐state syntheses at 850 °C for 7 days. Both cerium molybdates crystallize in space group C2/c with a = 1692.12(3), b = 1184.26(3), c = 1598.66(3) pm, and β = 108.4940(10)° (Z = 12) for Ce2Mo3O12 and a = 4609.00(12), b = 747.700(10), c = 1432.71(4) pm, and β = 101.023(2)° (Z = 8) for Ce4Mo7O27. The crystal structure of Ce2Mo3O12 comprises three crystallographically distinguishable Ce3+ cations with coordination numbers of 8 in shapes of trigonal dodecahedra. The five different Mo6+ cations are situated in the centers of noncondensed [MoO4]2- tetrahedra, and the overall arrangement of the mentioned building blocks is derived from the scheelite type. In the structure of Ce4Mo7O27, four crystallographically different Ce3+ cations with coordination numbers of 8 and 9 are found, as well as five non‐condensed [MoO4]2- tetrahedra and one pyroanionic [Mo2O7]2- unit.
  • Thumbnail Image
    ItemOpen Access
    Garnet-type Mn3Cr2(GeO4)3
    (2012) Lipp, Christian; Strobel, Sabine; Lissner, Falk; Niewa, Rainer
    Obtained by a chemical transport reaction, the manganese(II) chromium(III) germanate Mn3Cr2(GeO4)3 crystallizes isotypically with garnet.
  • Thumbnail Image
    ItemOpen Access
    Li4Ln[PS4]2Cl : chloride-containing lithium thiophosphates with lanthanoid participation (Ln = Pr, Nd and Sm)
    (2023) Lange, Pia L.; Bette, Sebastian; Strobel, Sabine; Dinnebier, Robert E.; Schleid, Thomas
    The synthesis and structural analysis of three new chloride-containing lithium thiophosphates(V) Li4Ln[PS4]2Cl with trivalent lanthanoids (Ln = Pr, Nd and Sm) are presented and discussed. Single crystals of Li4Sm[PS4]2Cl were obtained and used for crystal structure determination by applying X-ray diffraction. The other compounds were found to crystallize isotypically in the monoclinic space group C2/c. Thus, Li4Sm[PS4]2Cl (a = 2089.31(12) pm, b = 1579.69(9) pm, c = 1309.04(8) pm, β = 109.978(3)°, Z = 12) was used as a representative model to further describe the crystal structure in detail since Li4Pr[PS4]2Cl and Li4Nd[PS4]2Cl were confirmed to be isotypic using powder X-ray diffraction measurements (PXRD). In all cases, a trigonal structure in the space group R3̲ (e.g., a = 1579.67(9) pm, c = 2818.36(16) pm, c/a = 1.784, Z = 18, for Li4Sm[PS4]2Cl) displaying almost identical building units worked initially misleadingly. The structure refinement of Li4Sm[PS4]2Cl revealed bicapped trigonal prisms of sulfur atoms coordinating the two crystallographically distinct (Sm1)3+ and (Sm2)3+ cations, which are further coordinated by four anionic [PS4]3- tetrahedra. The compounds also contain chloride anions residing within channel-like pores made of [PS4]3- units. Eight different sites for Li+ cations were identified with various coordination environments (C.N. = 4-6) with respect to chlorine and sulfur. EDXS measurements supported the stoichiometric formula of Li4Ln[PS4]2Cl, and diffuse reflectance spectroscopy revealed optical band gaps of 2.69 eV, 3.52 eV, and 3.49 eV for Li4Sm[PS4]2Cl, Li4Nd[PS4]2Cl, and Li4Pr[PS4]2Cl, respectively. The activation energy for Li+-cation mobility in Li4Sm[PS4]2Cl was calculated as Ea(Li+) = 0.88 eV using BVEL, which indicates potential as a Li+-cation conductor.