Über die Reaktion von Tellur mit Wolframhalogeniden: Synthese und Struktur von Te7WOCl5, einer Verbindung mit einem polymeren Tellur-Kation

On the Reaction of Tellurium with Tungsten Halides: Synthesis and Crystal Structure of Te₇WOCl₅, a Compound with a Polymer Tellurium Cation The reaction of tellurium with WOCl₄ in the presence of a large excess of WCl₆ in a sealed evacuated glass ampoule at 150°C yields beside the main product Te₈(WCl₆)₂ a small amount of Te₇WOCl₅. The crystal structure determination (orthorhombic space group Pcca, lattice parameters at 173 K: a = 2 596.5(9) pm, b = 810.0(3) pm, c = 775.7(2) pm) shows that Te₇WOCl₅ is built of one-dimensional band shaped polymeric tellurium cations, one-dimensional associated pyramidal WOCl₄^? anions and of isolated Cl^? anions. Te₇WOCl₅ can thus be formulated as [Te₇²⁺]_n [WOCl₄^?]_n (Cl^?). The structure is closely related but not isotypic to the bromine containing analogue Te₇WOBr₅. The difference between the two structures lies in different directions of the polar [WOX₄^?]_n chains (X = Cl, Br). The strongly elongated thermal ellipsoid of one tellurium atom is shown to be caused by thermal vibration by determing the crystal structure of Te₇WOCl₅ at three different temperatures (223, 173 and 123 K). All displacement parameters of all atoms can be extrapolated to zero for 0 K.