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

Abstract

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.

LnSb2O4Br (Ln=Nd and Er) and Sb4O5Br2: Lanthanoid‐Bearing and ‐Free Antimony(III) Oxide Bromides

“…Two very similar monoclinic crystal structures exist for the composition Ln 5 Br 3 [AsO 3 ] 4 , since for Ln = La and Ce [8,9] they crystallize in the space group C2/c and find their analogues in the chloride series Ln 5 Cl 3 [AsO 3 ] 4 (Ln = LaÀ Pr). [10][11][12] For Ln = Pr, Nd, SmÀ Tb, [6,8,9,13] however, they adopt the space group P2/c and crystallize with the La 5 Cl 3 [SbO 3 ] 4 -type [13,14] crystal structure. Both feature edge-linked [LnO 8 ] 13À and [LnO 4 X 4 ] 9À polyhedra (X = Cl and Br) connected to layers.…”

“…With the element antimony there is a structurally relatively independent compound La 2 Sb 12 O 19 Br 4 , [8,14] crystallizing in the orthorhombic space group Pnma and displaying edge-linked [LnO 9 ] 15À polyhedra, isolated Br À anions and tubular [Sb 12 O 19 ] 2 + pipes, which run along the [010] direction. If one looks for the bismuth analogues among the antimonates LnSb 2 O 4 Br, there are two different representatives so far.…”