Sm2SCl4: A sulfide chloride of trivalent samarium with anti-SiS2-analogouschains (1)(infinity){[SSm4/2](4+)}

Pale-yellow single crystals of the chloride-richest rare-earth(III) sulfide chloride known to date with the composition Sm2SCl4 are obtained by the ox idation of samarium metal with sulfur in the molar ratio 2:3 in a melt of e xcess SmCl3 at 850 degrees C (7 d) in evacuated silica ampoules. The crysta l structure of Sm2SCl4 (monoclinic, C2/c; a = 1519.8(1), b = 639.43(6), c = 702.18(7) pm, beta = 98.057(8)degrees; Z = 4) exhibits Sm3+ in eightfold a nionic coordination of two S2- and six Cl- arranged as bicapped trigonal pr isms. Anti-SiS2-analogous chains of trans-edge linked [SSm4](10+) tetrahedr a according to (1)(infinity){[SSm4/2](4+)} running along [001] form the mai n structural feature and are hexagonally bundled as closest rod packing. Ch arge equalization and three-dimensional interconnection of these cationic c hains occur via two crystallographically different Cl- anions, each surroun ded by three Sm3+.