Rheniumselenidtelluride Re2SexTe5–x: Die Struktur von Re6Se8Te7

Rhenium Selenidetellurides Re₂Se_xTe_5–x: The Structure of Re₆Se₈Te₇ Well-crystallized rhenium selenidetellurides of the Re₂Te₅-type structure were prepared from the elements in evacuated sealed quartz glas tubes at 1 130 K within 14 d. The orthorhombic lattice parameters of the phases shrink with increasing selenium content from a = 1 304.9(1) ? 1 255.8(2) pm, b = 1 297.5(1) ? 1 260.0(2) pm, and c = 1 425.1(1) ? 1 408.2(1) pm. The phase width ends at composition Re₂Se_2.7Te_2.3. An X-ray structure analysis of a crystal of composition Re₆Se₈Te₇ was performed. Selenium and tellurium atoms differ structurally completely: Whereas the selenium atoms are separated within distorted octahedral [Re₆Se₈] clusters, the tellurium atoms form homonuclear bonded bicyclic [Te(Te₃)₂] units. They also link the clusters which are arranged according to the motif of a cubic closest packing.