The crystal structure of Cu2.31TeS0.32 - a condensed cluster compound

The crystal structure of Cu2.31TeS0.32, a sulfur-pool member of the solid s olution series Cu61.3Te18.3S20.5-Cu61.9Te35.7S2.36 prepared at 675 degrees C, was deter-mined and refined from single-crystal diffractometer X-ray dat a (R = 0.044). The quenched statistical cubic structure (a = 14.836(4) Angs trom, space group F4(1)32) consists at room temperature of two interpenetra ting tetrahedral frameworks of icosahedral tellurium cages which enclose ic osahedral clusters of half-occupied Cu positions centred by additional, ful ly occupied central copper sites. In one subset, statistically occupied sul fur tetrahedra occur in the tellurium cages, centred on this central Cu sit e. The CU2.31TeS0.32 structure is a stuffed derivative of Cr3Si (structure type Al3) and shows affinities to the structures of Cuy(9.1)TeSb(3), the Ag 8GeTe6 family and some metal clusters, especially [Cu26Se13(PEt2Ph)(14)] an d [Au13Cl2(PMe2Ph)(10)].