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The ytterbium(III) oxide bromide oxidotellu-rate(IV) Yb3O2Br[TeO3]2 was obtained from a mixture of Yb2O3, YbBr3 and TeO2 in a molar ratio of 2:1:2 along with an excess of KBr as fluxing agent in evacuated fused silica ampoules after 10 days at T = 800 °C and subsequent slow cooling to room temperatures as colorless, plate-shaped single crystals. Its triclinic crystal structure (a = 663.97(5), b = 697.46(5), c = 1080.15(8) pm, α = 105.102(3), β = 90.931(3), γ = 100.034(3)°; Z = 2, space group: P 1 ‾ $‾{1}$) displays three crystallographically different Yb3+ cations with coordination numbers of six, seven and eight. Six out of eight distinct oxygen atoms belong to two independent ψ1-tetrahedral [TeO3]2−anions, whereas the other two represent O2− anions in tetrahedral coordination of four Yb3+ cations each, not having any contact to tellurium. Condensed via common vertices and edges, these [OYb4]10+ tetrahedra form cationic layers ∞ 2 ${}_{\infty }{}^{2}$ {[O2Yb3]5+}, which spread out parallel to the (001) plane. Two discrete [TeO3]2− groups and one Br− anion per formula unit take care of their three-dimensional interconnection along [001] and the overall charge balance of Yb3O2Br[TeO3]2. Remarkable interactions between the lone pair of electrons at the Te4+ cations of the ψ1-tetrahedral [TeO3]2− anions and those at the Br− anions are discussed. [ABSTRACT FROM AUTHOR]

By fusing Lu2O3 and TeO2 in a molar ratio of 1:3 in a CsCl flux, colorless single crystals of the lutetium(III) oxotellurate(IV) Lu2Te3O9 could be obtained as first representative of the structurally so far unknown C-type for the composition M2Te3O9. The title compound crystallizes triclinically in space group P $\bar{1}$ with a = 689.67(4) pm, b = 1320.91(8) pm, c = 1450.06(9) pm, α = 110.057(3)°, β = 90.606(3)°, γ = 100.125(3)°, and Z = 6. The crystal structure contains six different Lu3+ cations in eightfold (Lu1 and Lu2: trigonal dodecahedra) and sevenfold (Lu3 and Lu6: monocapped trigonal prisms; Lu4 and Lu5: pentagonal bipyramids) oxygen coordination. These lutetium-oxygen polyhedra ( d(Lu-O) = 214-274 pm) are condensed to serrated layers according to 2∞{[Lu6O26]34-} that are stacked along [100]. The oxotellurate(IV) partial structure consists of basically nine crystallographically independent [TeO3]2- ( d(Te-O) = 184-196 pm) units connecting the above-mentioned layers to a three-dimensional framework. Strong secondary Te4+ ···O2- interactions between adjacent [TeO3]2- entities as common feature in the crystal structures of all known ternary lanthanoid(III) oxotellurates(IV) are also present in the crystal structure of Lu2Te3O9. Depending upon the range of these secondary contacts taken into account, the [TeO3]2- units are linked to form one-dimensional strands ( d(Te ···O) = 237-272 pm) like in B-type Dy2Te3O9 or even two-dimensional layers emerge ( d(Te ···O) = 237-285 pm). [ABSTRACT FROM AUTHOR]

The new oxotellurate(VI) Gd2TeO6 was synthesized by solid-state reaction of equimolar mixtures of Gd2O3 and TeO3 in evacuated silica tubes at 800°C within 10 days. This compound crystallizes in the orthorhombic system with the space group P212121 (no. 19) and the lattice constants a=532.52(4), b=916.03(8), c=1004.60(9) pm (Z=4). The crystal structure was determined by X-ray single-crystal diffraction techniques and refined with R1=0.028, wR2=0.059 and a Flack-x parameter of −0.002(2) for 2157 unique reflections. In the La2TeO6-type crystal structure of Gd2TeO6, the Gd3+ cations occupy two of the nine independent atomic positions and are coordinated sevenfold by oxygen. Separately from each other, both coordination polyhedra [GdO7] build zigzag chains along [100] via common edges (Gd1) and corners (Gd2), respectively. Each of the chains order as hexagonal rod packing. Finally, both of them combine by linkage via edges and corners again to form a complex 3∞{[GdO3]3−} framework. The isolated [TeO6]6− octahedra reside in the oval channels of this arrangement. [Copyright &y& Elsevier]