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.