Die Kristallstruktur von [(CH3)4N]2TeCl6 und über die Einschlußverbindung [(CH3)4N]2(CH3CN)TeCl6

Both title compounds show an antifluorite-like arrangement of (CH3)4N+ cations and TeCl6 2- anions. The remaining octahedral holes in this array can be filled with CH3CN molecules forming the inclusion compound by crystallization from CH3CN solution. [(CH3)4N]2TeCl6 (space group Fd3c with a = 25.791(3) Å at 265(5) K and Z = 32) contains almost regular TeCl6 2- octahedra. In contrast, in [(CH3)4N]2(CH3CN)TeCl6 (space group Cmcm with a = 12.765(6), b = 14.349(7), c = 12.716(3) Å and Z = 4) the anion is statically distorted with the approximate point symmetry 4 mm. At temperatures above 320 K the solvent molecules can be removed yielding the Fd3c phase. Finally, structural relationships between antifluorite-like phases A2BX6 and elpasolites A2B'BX6 considering halogenides and cyanides are discussed