Single Crystals of NaPrTe2 with LiTiO2‐Type Structure

During attempts to synthesize rare‐earth nitride tellurides black and bead‐shaped single crystals of the title compound sodium praseodymium(III) ditelluride (NaPrTe₂) were obtained as a by‐product by reacting a mixture of praseodymium, sodium azide (NaN₃) and tellurium at 900 °C for seven days in evacuated torch‐sealed silica vessels. NaPrTe₂ crystallizes cubic (space group: Fd3¯m, Z = 16; a = 1285.51(9) pm, V_m = 79.96(1) cm³/mol, R₁ = 0.028 for 146 unique reflections) and exhibits the Na⁺ and Pr³⁺ cations in slightly distorted octahedra of six telluride anions (d(Na—Te) = 325 pm, d(Pr—Te) = 317 pm) each. The main characteristics of this new structure type for alkali‐metal rare‐earth(III) dichalcogenides can be derived from the rock‐salt type structure (NaCl, cubic closest‐packed Te^2— arrangement, all octahedral voids occupied with Na⁺ and Pr³⁺) with alternating layers consisting of Na⁺ and Pr³⁺ cations in a ratio of 3:1 and 1:3, respectively, piled along the [111] direction.     

A Potential Method Using Ge{iPrNC[N(SiMe3)2]NiPr}2, (Et3Si)2Te and Anhydrous Hydrazine for Germanium Tellurides

A germanium(II)‐guanidine derivative of formula Ge{iPrNC[N(SiMe₃)₂]NiPr}₂ ( 1 ) was synthesized and characterized by ¹H NMR, ¹³C NMR, elemental analysis, and X‐ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et₃Si)₂Te. Solution reaction of compound 1 , (Et₃Si)₂Te, and anhydrous hydrazine was investigated to pre‐identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides.     

Structural Relations in the Family of Nonmetallic Filled β-Manganese Phases: The new members AGa6Te10 (A: Sn,Pb) and PbIn6Te10

Nonmetallic filled β-manganese phases form a new class of solids with a wide spaced (“eutactical”) partial structure of nonmetal atoms (Te, I), which is topologically equivalent to the arrangement of manganese atoms in cubic β-Mn (a = 6.315 Å, P4₁32, Z = 20), a manganese polymorph crystallizing in a tetrahedrally close packed structure. Different fractions of the 100 tetrahedral and 4 metaprismatic holes per unit cell of the β-Mn like arrangement of nonmetal atoms are occupied by metal atoms or pairs of covalently bonded metal atoms, leading to the different chemical compositions M₇Te₁₀, AM₆Te₁₀, Ag₂Ga₆Te₁₀, RbX₄I₅ (M: Al, Ga, In; A: Ca, Pb, Sn; X: Ag, Cu;). Basic structural properties and structural relations between the members of this new family of solids are discussed. In addition we present structural data for three new members of the family of filled β-Mn phases: SnGa₆Te₁₀ (single crystal data: a = 10.203 Å, α = 89.94°, space group R32, Z = 2) PbIn₆Te₁₀ (single crystal data: a = 10.619 Å, R32, Z = 2) and PbGa₆Te₁₀ (powder data: a = 10.237 Å, α = 89.93°, R32, Z = 2).     

Die metallreiche Schichtstruktur von Ta6STe3

The Metal‐rich Layer Structure of Ta₆STe₃ Ta₆S_1+xTe_3–x was prepared from an appropriate mixture of 2 H–Ta_1.3S₂, TaTe₂, and Ta in a fused tantalum tube at 1273 K within 3 d. The results of a X‐ray single crystal structure analysis for a phase near the Te‐rich limit of the homogeneity range are reported. Ta₆S_1.00Te_3.00(1) crystallizes in the triclinic space group P1, a = 993.14(8) pm, b = 1032.18(8) pm, c = 1378.78(11) pm, α = 79.32(1)°, β = 81.36(1)°, γ = 85.74(1)°, Z = 6, Pearson symbol aP60, 6048 I_o > 2σ (I_o), 286 variables, wR₂ = 0.067. The metal‐rich layer structure of Ta₆STe₃ comprises distorted icosahedral Ta₁₃ clusters and related deltahedral cluster fragments complemented by chalcogen atoms. The centred clusters consist of 11, 12, 13, 14, or 16 atoms. They interpenetrate into lamellae in which the tantalum and chalcogen atoms are spatially segregated according to [Q–Ta₃–Q]. The signature of the structure is a lenticular heptagonal antiprismatic Ta₃₀ cluster which seems to be excised from the pentagonal antiprismatic columnar structure of Ta₆S. The Ta₃₀ clusters and distorted icosahedral Ta₁₃ clusters are connected and fused into puckered layers. The rest of the tantalum valences are used for heteronuclear bonding. The chalcogen atoms having three to six next tantalum atoms coat the corrugated, tetrahedrally close‐packed layers. Ta₆STe₃ is a moderate metallic conductor (ρ_{293 K} = 3 × 10^–4 Ωcm) exhibiting typical temperature independent paramagnetic properties.     

Two Alkali‐Metal Yttrium Tellurides: Single Crystals of Trigonal KYTe2 and Hexagonal RbYTe2

While attempting to synthesize the potassium and rubidium copper diyttrium tetratellurides KCuY₂Te₄ and RbCuY₂Te₄ in analogy to CsCuY₂Te₄ from 1:1:4‐molar mixtures of the elements (copper, yttrium and tellurium) with an excess of KBr or RbBr as flux and potassium or rubidium source, brown plate‐shaped crystals of KYTe₂ and RbYTe₂ with triangular cross‐section were obtained instead after 14 days at 900 °C in torch‐sealed evacuated silica tubes. These new ternary yttrium tellurides crystallize in the trigonal (KYTe₂) or hexagonal system (RbYTe₂) with space group R m (no. 166) or P6₃/mmc (no. 194), respectively. With unit cell dimensions of a = 439.51(2) pm, c = 2255.48(9) pm (c/a = 5.132) for KYTe₂ and a = 443.26(2) pm, c = 1729.15(7) pm (c/a = 3.901) for RbYTe₂, both crystal structures exhibit cadmium‐halide analogous layers spreading out parallel to the (001) planes, which are formed by edge‐condensation of the involved [YTe₆]^9– octahedra (d(Y³⁺–Te^2–) = 308–309 pm). Charge compensation and three‐dimensional linkage of these anionic layers are achieved by monovalent interlayer alkali‐metal cations residing in trigonal antiprismatic (K⁺ in α‐NaFeO₂‐type KYTe₂, d(K⁺–Te^2–) = 324 pm, 6×) or prismatic coordination (Rb⁺ in β‐RbScO₂‐type RbYTe₂, d(Rb⁺–Te^2–) = 365 pm, 6×) of six Te^2– ions each.     

Csp-tellurium copper cross-coupling: synthesis of alkynyl tellurides a novel class of antidepressive-like compounds

We present here the results on the synthesis of functionalized alkynyl tellurides using the reaction of vinyl, alkynyl, and aryl tellurides with several alkynyl iodides catalyzed by copper iodide. The reaction proceeded cleanly under mild reaction conditions, at room temperature, in the absence of base and ligand giving alkynyl tellurides in acceptable yields. The obtained compounds 3a-c and 3m-o were screened for antidepressive-like activity using the tail suspension test (TST) in mice. Compounds 3a-c and 3m-o administered at 10 mg/kg by oral route produced a significant antidepressant-like effect on the TST in mice.     

Syntheses and structures of CsHo3Te5 and Cs3Tm11Te18 and the electronic structure of CsHo3Te5

Single crystals of CsHo₃Te₅ and Cs₃Tm₁₁Te₁₈ have been grown as byproducts in the synthesis of CsLnZnTe₃ (Ln=Ho or Tm) through the reaction of Ln, Zn, and Te with a CsCl flux at 850 °C. The crystal structures have been determined from single-crystal X-ray diffraction data. CsHo₃Te₅ crystallizes in space group Pnma of the orthorhombic system whereas Cs₃Tm₁₁Te₁₈ crystallizes in the space group C2/m of the monoclinic system. Each of the compounds adopts a three-dimensional structure; each possesses tunnels built from LnTe₆ octahedra that are filled with Cs atoms. The pseudo-rectangular tunnel in CsHo₃Te₅ is large enough in cross-section to accommodate two symmetrically equivalent Cs atoms. In the Cs₃Tm₁₁Te₁₈ structure there are two different sized tunnels: the smaller one is only large enough to host one Cs atom per unit cell whereas the larger one can accommodate two Cs atoms. The electronic structure of CsHo₃Te₅ was calculated. The band gap is estimated to be about 1.2 eV, consistent with the black color of the crystals.     

Thermodynamic properties of chromium—Tellurium alloys

Tellurium vapor pressures of chromium—tellurium alloys were determined in the range of NiAs-type structures between 800 and 1,300 K and between 55 and 62 at% Te by an isopiestic method. The partial molar quantities of tellurium were derived, and the results critically compared with data reported in the literature.

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Thermodynamische Eigenschaften von Chrom—Tellur-Legierungen

Zusammenfassung Die Tellurdampfdrücke von Chrom—Tellur-Legierungen wurden mit Hilfe einer isopiestischen Methode im Bereich der Phasen mit NiAs-ähnlichen Strukturen zwischen 800 und 1300 K und zwischen 55 und 62 At% Te bestimmt. Die partiellen molaren Eigenschaften von Tellur wurden daraus abgeleitet, und die Resultate kritisch mit Literaturwerten verglichen.