The Triclinic Lanthanoid(III) Halide Oxidoarsenates(III) Sm3Cl2[As2O5][AsO3] and Tm3Br2[As2O5][AsO3] |
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| Authors: | Felix C. Goerigk Svetlana Schander Mathias S. Wickleder Thomas Schleid |
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| Affiliation: | 1. Institute for Inorganic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany;2. Institute for Pure and Applied Chemistry, University of Oldenburg, 26129 Oldenburg, Germany;3. Institute for Inorganic Chemistry, University of Cologne, 50939 Cologne, Germany |
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| Abstract: | 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. |
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| Keywords: | Lanthanoids Rare-earth metal compounds Halide oxidoarsenates(III) Structure elucidation Solid-state synthesis |
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