CuYS2: A ternary copper(I) yttrium(III) sulfide with chains (1)(infinity){[Cu(S1)(3/3)(S2)(1/1)](3-)} of cis-edge connected [CuS4](7-) tetrahedra

Pale yellow, lath-shaped single crystals of the ternary copper(I) yttrium(I II) sulfide CuYS2 are obtained by the oxidation of equimolar mixtures of th e metals (copper and yttrium) with sulfur in the molar ratio 1:1:2 within f ourteen days at 900 degrees C in evacuated silica ampoules, while the prese nce of CsCl as fluxing agent promotes their growth. The crystal structure o f CuYS2 (ortharhombic, Pnma; a = 1345.3(1), b = 398.12(4), c = 629.08(6) pm , Z = 4) exhibits chains of cis-edge linked [CUS4](7-) tetrahedra with the composition (1)(proportional to)([Cu(S1)(3/3)(S2)(1/1)](3-)) running along [010] which are hexagonally bundled as closest rod packing. Charge equaliza tion and three-dimensional interconnection of these anionic chains occur vi a octahedrally coordinated Y3+ cations. These are forming together with the S2- anions a network (3)(proportional to)[Y(S1)(3/3)(S2)(3/3)](-) Of verte x- and edge-shared [YS6](9-) octahedra with ramsdellite topology. The metal l-sulfur distances of the [CuS4](7-) tetrahedra (230 (Cu-S2), 232 (Cu-S1), and 253 pm (Cu-S1', 2x)) cover a very broad interval, whilst these (Y-S: 26 7-280 pm) within the [YS6](9-) octahedra range rather closely together.