The Triclinic Lanthanoid(III) Halide Oxidoarsenates(III) Sm₃Cl₂[As₂O₅][AsO₃] and Tm₃Br₂[As₂O₅][AsO₃]

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.

Composition and Crystal Structure of SmSb2O4Cl Revisited – and the Analogy of Sm1.5Sb1.5O4Br

“…Two different kinds of oxidoarsenate(III) units are present in the triclinic crystal structure of compounds with the structured formula Ln 3 X 2 [As 2 O 5 ][AsO 3 ] (Ln = Sm -Gd with X = Cl, Ln = Ho -Yb with X = Br): [AsO 3 ] 3and [As 2 O 5 ] 4anions. [8,9] Additional O 2-anions, which are not bonded to any pnictogen atom, characterize the crystal structures of the tetragonal lan-analysis revealed the actual compositions of the investigated antimony(III) compounds, which can be understood as heavily Sm 3+doped derivatives of "SmSb 2 O 4 X" hosts at the Sb 3+ site. (Sm1) 3+ is coordinated eightfold by oxygen atoms in the shape of a cube.…”

Three New Lanthanum Oxoantimonate(III) Halides: Synthesis and Crystal Structure of La5Cl3[SbO3]4, La2Sb12O19Br4 and La2Sb12O19I4

“…Namely, the linkage occurs once via the (Cl2) − anions, which edge-link the polyhedra along the b-axis, forming one-dimensional double strands. A quite similar bonding situation is found in the rare-earth metal(III) halide oxoarsenates(III) RE 3 X 2 [As 2 O 5 ][AsO 3 ] (RE = Y, Sm-Gd, Ho-Yb and X = Cl and Br) [3,25]. However, these chains are still corner-linked to each other via the (Cl1)anions here, turning the double strands into a two-dimensional bilayer (Figure 6, top), which can be described Figure 8 shows a section of the crystal structure of La5Cl3[SbO3]4, emphasizing the cell edges and the different coordination polyhedra.…”

Enhancing the Analysis of Eu3+ Photoluminescence in Coordination Compounds in the Solid State by Determining their Refractive Index

“…Due to the characteristic 4 f-4 f luminescence of trivalent lanthanides, their compounds are widely investigated as phosphors. Photoluminescence properties of Ln 3 + are generally studied in inorganic [1][2][3] or coordination compounds. [4][5][6][7][8][9][10][11] Furthermore, these metal ions could be used as dopants [12][13][14][15][16] or embedded in polymeric films.…”