Synthese und Kristallstruktur von Te4 2+(WCl6-)2 / Synthesis and Crystal Structure of Te4 2+(WCl6 -)2

Abstract

WCl6 reacts with two equivalents of tellurium in a sealed evacuated ampoule in the temperature range from 170 to 190 °C to give Te4 2+(WCl6 -)2. Under the same conditions with one equivalent of tellurium WCl5 yields Te4 2+(WCl6 -)2 and WCl4. Te4(WCl6), formes black crystals, which are sensitive to moist air. It decomposes at temperatures above 300° C to Te and WCl6. The crystal structure determination (lattice constants a = 638.9(1), b = 753.2(2), c = 1102.0(5) pm, α = 101.19(2)°, β = 102.85(2)°, γ = 90.21(1)°, Z = 1, triclinic space group P 1̄, 3572 unique reflections for 82 parameters, final R = 0.026) shows the nearly ideal square Te4 2+ cation with Te–Te distances of 268.8 and 268.7 pm and markedly distorted WCl6 – octaedra with W–Cl bond length from 227.5 to 237.3 pm. The structure involves interionic Te–Cl contacts as short as 319 pm.