Polymere,bandförmige Tellurkationen in den Strukturen des Chloroberyllats Te7[Be2Cl6] und des Chlorobismutats (Te4)(Te10)[Bi4Cl16]

Polymeric, Band Shaped Tellurium Cations in the Structures of the Chloroberyllate Te₇Be₂Cl₆] and the Chlorobismutate (Te₄)(Te₁₀)Bi₄Cl₁₆] Te₇Be₂Cl₆] is obtained at 250 °C in an eutectic Na₂BeCl₄] / BeCl₂ melt from Te, TeCl₄ und BeCl₂ in form of black crystals, which are sensitive towards hydrolysis in moist air. (Te₄) (Te₁₀)Bi₄Cl₁₆] is prepared from Te, TeCl₄ und BiCl₃ by chemical vapour transport in sealed evacuated glass ampoules in a temperature gradient 150 ° → 90 °Cin form of needle shaped crystals with a silver lustre. The structures of both compounds were determined based on single crystal X‐ray diffraction data (Te₇Be₂Cl₆]: orthorhombic, Pnnm, Z = 2, a = 541.60(3), b = 974.79(6), c = 1664.4(1) pm; (Te₄)(Te₁₀)Bi₄Cl₁₆]: triclinic, P1¯, Z = 2, a = 547.2(3), b = 1321.1(7), c = 1490(1) pm, α = 102.09(5)°, β = 95.05(5)°, γ = 96.69(4)°). The structure of Te₇Be₂Cl₆] consists of one‐dimensional polymeric cations (Te₇²⁺)_n which form folded bands and of discrete Be₂Cl₆]^2— anions which form double tetrahedraconnected by a common edge. By a different way of folding compared with the cations present in the structures of Te₇MOX₄]X (M = Nb, W; X = Cl, Br) the (Te₇²⁺)_n cation in Te₇Be₂Cl₆]represents a new, isomeric form. The structure of (Te₄)(Te₁₀)Bi₄Cl₁₆] contains two different polymeric cations. (Te₁₀²⁺)_n consists of planar Te₁₀ groups in the form of three corner‐sharing Te₄ rings connected to folded bands. (Te₄²⁺)_n forms in contrast to the so far notoriously observed discrete, square‐planar E₄²⁺ ions a chain of rectangular planar Te₄ rings (Te—Te 274 and 281 pm) connected by Te‐Te bonds of 297 pm. Bi₄Cl₁₆]^4— has a complex one‐dimensional structure of edge‐ and corner‐sharing BiCl₇ units.