Browsing by Author "Goerigk, Felix C."

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    Composition and crystal structure of SmSb2O4Cl revisited : and the analogy of Sm1.5Sb1.5O4Br
    (2019) Goerigk, Felix C.; Schleid, Thomas
    The quaternary halide‐containing samarium(III) oxidoantimonates(III) Sm1.3Sb1.7O4Cl and Sm1.5Sb1.5O4Br were synthesized through solid‐state reactions from the binary components (Sm2O3, Sb2O3 and SmX3, X = Cl and Br) at 750 °C in evacuated fused silica ampoules. They crystallize tetragonally in the space group P4/mmm, like the basically isotypic bismuthate(III) compounds SmBi2O4Cl and SmBi2O4Br, but show larger molar volumes and therefore contradict an ideal composition of “SmSb2O4X” (X = Cl and Br). Both single‐crystal X‐ray diffraction and quantitative electron‐beam microprobe analysis revealed the actual compositions of the investigated antimony(III) compounds, which can be understood as heavily Sm3+‐doped derivatives of “SmSb2O4X” hosts at the Sb3+ site. (Sm1)3+ is coordinated eightfold by oxygen atoms in the shape of a cube. The mixed‐occupied (Sb/Sm2)3+ cation has four oxygen atoms and four halide anions as neighbors forming a square antiprism. The oxygen atoms and anions establish alternating layers parallel to the ab‐plane, which alternate when stacked along [001].
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    ItemOpen Access
    Synthesis and crystal structure of the short LnSb2O4Br series (Ln = Eu-Tb) and luminescence properties of Eu3+-doped samples
    (2020) Goerigk, Felix C.; Paterlini, Veronica; Dorn, Katharina V.; Mudring, Anja-Verena; Schleid, Thomas
    Pale yellow crystals of LnSb2O4Br (Ln = Eu-Tb) were synthesized via high temperature solid-state reactions from antimony sesquioxide, the respective lanthanoid sesquioxides and tribromides. Single-crystal X-ray diffraction studies revealed a layered structure in the monoclinic space group P21/c. In contrast to hitherto reported quaternary lanthanoid(III) halide oxoantimonates(III), in LnSb2O4Br the lanthanoid(III) cations are exclusively coordinated by oxygen atoms in the form of square hemiprisms. These [LnO8]13- polyhedra form layers parallel to (100) by sharing common edges. All antimony(III) cations are coordinated by three oxygen atoms forming ψ1-tetrahedral [SbO3]3- units, which have oxygen atoms in common building up meandering strands along [001] according to {[SbO𝑣2/2O𝑡1/1]-}-1 (v = vertex-sharing, t = terminal). The bromide anions are located between two layers of these parallel running oxoantimonate(III) strands and have no bonding contacts with the Ln3+ cations. Since Sb3+ is known to be an efficient sensitizer for Ln3+ emission, photoluminescence studies were carried out to characterize the optical properties and assess their suitability as light phosphors. Indeed, for both, GdSb2O4Br and TbSb2O4Br doped with about 1.0-1.5 at-% Eu3+ efficient sensitization of the Eu3+ emission could be detected. For TbSb2O4Br, in addition, a remarkably high energy transfer from Tb3+ to Eu3+ could be detected that leads to a substantially increased Eu3+ emission intensity, rendering it an efficient red light emitting material.
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    Three new lanthanum oxoantimonate(III) halides : synthesis and crystal structure of La5Cl3[SbO3]4, La2Sb12O19Br4 and La2Sb12O19I4
    (2023) Locke, Ralf J. C.; Bozenhardt, Kim-Natalie; Goerigk, Felix C.; Schleid, Thomas
    It was possible to synthesize colorless single crystals of La5Cl3[SbO3]4 (block-shaped) as well as La2Sb12O19Br4 and LaSb12O19I4 (both needle-shaped), representing three new compounds from the system of lanthanum oxoantimonate(III) halides, which have not been described in the literature before. La5Cl3[SbO3]4 crystallizes in the monoclinic space group P2/c with the lattice parameters a = 895.82(5) pm, b = 564.28(3) pm, c = 1728.19(9) pm, and β = 90.007(2)° for Z = 2. This layered compound contains isolated ψ1-tetrahedral [SbO3]3- units, square hemiprisms [LaO8]13-, and antiprisms [LaO4Cl4]9-, La2Sb12O19Br4 and LaSb12O19I4 crystallize isotypically in the orthorhombic space group Pnma with a = 3184.69(19) pm, b = 417.78(3) pm, c = 1019.85(6) pm for the bromide and a = 3215.08(19) pm, b = 419.94(3) pm, c = 1062.89(6) pm for the iodide. Instead of isolated [SbO3]3- anions, semi-tubular features 1∞{[Sb12O19]2-} are present, which consist mainly of [SbO4]5- and few [SbO3]3- units with stereochemically active electronic lone pairs at their Sb3+ centers. Within these so-called “double-halfpipes”, La3+ is surrounded by nine oxygen atoms as [LaO9]15- polyhedron without any contact with X- anions. Single-crystal Raman measurements were performed for La5Cl3[SbO3]4 and LaSb12O19I4, and La5Cl3[SbO3]4 was structurally compared with the isostoichiometric, but not isotypic La5F3[SbO3]4.
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    ItemOpen Access
    The triclinic lanthanoid(III) halide oxidoarsenates(III) Sm3Cl2[As2O5][AsO3] and Tm3Br2[As2O5][AsO3]
    (2020) Goerigk, Felix C.; Schander, Svetlana; Wickleder, Mathias S.; Schleid, Thomas
    Pale yellow single crystals of the composition Ln3X2[As2O5][AsO3] (Ln = Tm for X = Br and Ln = Sm for X = Cl) were obtained via solid‐state reactions in the systems Ln2O3/As2O3 from sealed silica ampoules using different halides as fluxing agents. Sm3Cl2[As2O5][AsO3] and Tm3Br2[As2O5][AsO3] crystallize isotypically in the triclinic space group P1 with Z = 2 and cell parameters of a = 543.51(4) pm, b = 837.24(6) pm, c = 1113.45(8) pm, α = 90.084(2)°, β = 94.532(2)°, γ = 90.487(2)° for the samarium and a = 534.96(4) pm, b = 869.26(6) pm, c = 1081.84(8) pm, α = 90.723(2)°, β = 94.792(2)° γ = 90.119(2)° for the thulium compound. The isotypic crystal structure of both representatives exhibits three crystallographically different Ln3+ cations, each with a coordination number of eight. (Ln1)3+ and (Ln2)3+ are only coordinated by three oxygen atoms, whereas (Ln3)3+ shows additional contacts to halide anions in forming square [LnO4X4]9- antiprisms. All As3+ cations are surrounded by three oxygen atoms in the shape of isolated [AsO3]3- ψ1‐tetrahedra. They occur either isolated or condensed as pyroanionic [As2O5]4- units with a bridging oxygen atom. In both anions, non‐binding lone‐pair electrons are present at the As3+ cations with a pronounced stereochemically active function.