Lu2Te3O9: The First Example of the TriclinicC-Type Lanthanoid(III) Oxotellurates(IV) with the CompositionM2Te3O9

C-type Yb2Te3O9

The title compound, diytterbium enneaoxidotritellurate(IV), was obtained in its C-type crystal structure from the binary oxides at 1073 K using a CsCl flux. It crystallizes isotypically with C-type Tm2Te3O9 and Lu2Te3O9, closing this gap of knowledge.

Synthesis and crystal structure of two scandium oxotellurates(IV): Sc2Te3O9 and Sc2Te4O11

The two new scandium oxotellurates(IV) Sc2Te3O9 and Sc2Te4O11 were synthesized through firing appropriate mixtures of Sc2O3, TeO2 and CsBr (as flux) in evacuated glassy silica ampoules at 850 °C for 10 days. Both of them crystallize in the monoclinic space group P21/c with Z = 4 (Sc2Te3O9: a = 523.36(3), b = 2438.23(14), c = 731.98(4) pm, β = 116.221(3)°; Sc2Te4O11: a = 949.51(6), b = 779.12(5), c = 1341.93(9) pm, β = 90.829(3)°). Both crystal structures contain two crystallographically unique Sc3+ cations. In the case of Sc2Te3O9, they reside in six- and sevenfold oxygen coordination arranged as distorted uncapped or capped octahedra, while for Sc2Te4O11, they only exhibit six oxygen atoms in the coordination polyhedra, but one of them has also a certain tendency to thrive for a higher coordination number (C.N. = 6 + 1). The [(Sc1)O6)]9− and [(Sc2)O6+1)]11− polyhedra in Sc2Te3O9 are condensed via common edges to form serrated   ∞ 1 { [ Sc 2 O 6 / 1 t O 1 / 2 v O 4 / 2 e ] 11 − } ${\text{ }}_{\infty }^{1}\left\{{\left[{\text{Sc}}_{2}{\text{O}}_{6\text{/}1}^{\text{t}}{\text{O}}_{1\text{/}2}^{\text{v}}{\text{O}}_{4\text{/}2}^{\text{e}}\right]}^{11-}\right\}$ chains running along [100], whereas the two [ScO6]9− octahedra in Sc2Te4O11 only share common vertices, generating   ∞ 1 { [ Sc 2 O 6 / 1 t O 3 / 2 v ] 9 − } ${\text{ }}_{\infty }^{1}\left\{{\left[{\text{Sc}}_{2}{\text{O}}_{6\text{/}1}^{\text{t}}{\text{O}}_{3\text{/}2}^{\text{v}}\right]}^{9-}\right\}$ double strands along [010]. In both compounds, the three-dimensional framework and the charge balance are accomplished by the discrete ψ1-tetrahedral [TeO3]2− anions with non-bonding lone-pair electrons located at their central Te4+ cations. Moreover, strong secondary Te4+···O2− interactions, which are generally quite common for rare earth metal(III) oxotellurates(IV), occur in both crystal structures, but much more pronounced in Sc2Te4O11, where three quarters of the Te4+ cations reside in the centers of ψ eq 1 ${{\psi}}_{\text{eq}}^{1}$ -trigonal bipyramids [TeO4]4− as compared to Sc2Te3O9, which can well be written as Sc2[TeO3]3.

Das Ytterbium(III)-Oxidbromid-Oxidotellurat(IV) Yb3O2Br[TeO3]2

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.

The complete series of sodium rare-earth metal(III) chloride oxotellurates(IV) Na2 RE 3Cl3[TeO3]4 (RE = Y, La–Nd, Sm–Lu)

The complete series of sodium rare-earth metal(III) chloride oxotellurates(IV) with the composition Na2 RE 3Cl3[TeO3]4 (RE = Y, La–Nd, Sm–Lu) has been synthesized via solid-state reactions. For these conversions mixtures of the respective rare-earth metal(III) oxides, tellurium dioxide and sodium chloride as flux and reactant were prepared, intimately ground and heated for 5 days at 1225 K. The almost colorless single crystals were characterized via single-crystal X-ray diffractometry. In the monoclinic crystal structure of these compounds two crystallographically different rare-earth metal(III), but only one sodium cation sites occur. [REO8]13− polyhedra around both RE 3+ positions as well as sodium-centered polyhedra [NaO4Cl4]8− form layers via different connectivity modes. These layers spread out parallel to the (001) plane and arrange alternatingly resulting in the three-dimensional network of the Na2 RE 3Cl3[TeO3]4 structure, where the Te4+ lone-pair cations at two different sites work as linkers by forming isolated ψ 1-tetrahedra [TeO3]2−. Some of these compounds were represented before in different settings of space group C2/c. Now the complete series of the Na2 RE 3Cl3[TeO3]4 representatives with RE = Y, La–Nd, Sm–Lu is described consistently for a better comparison and understanding. Additionally, a single crystal of Na2Pr3Cl3[TeO3]4 was measured via energy dispersive X-ray analysis to verify the included elements, powder samples of Na2Nd3Cl3[TeO3]4 were characterized by X-ray diffractometer data for a phase-purity check and a single-crystal Raman spectrum of Na2Yb3Cl3[TeO3]4 served for proving the signature of discrete [TeO3]2− anions.