Inhaltsu È bersicht. Blaûgelbe Einkristalle des bislang chloridreichsten Selten-Erd(III)-Sulfidchlorids mit der Zusammensetzung Sm 2 SCl 4 erha È lt man durch Oxidation von Samarium-Metall mit Schwefel im molaren Verha È ltnis von 2 : 3 in einer Schmelze aus u È berschu È ssigem SmCl 3 bei 850 °C (7 d) in evakuierten Quarzglasampullen. In der Kristallstruktur von Sm 2 SCl 4 (monoklin, C2/c; a = 1519,8(1); b = 639,43(6); c = 702,18(7) pm; b = 98,057(8)°; Z = 4) wird Sm 3+ von insgesamt acht Anionen (zwei S 2± und sechs Cl ± ) in Form von doppelt u È berkappten trigonalen Prismen koordiniert. Entlang [001] bilden anti-SiS 2 -analoge Ketten trans-kantenverknu È pfter [SSm 4 ] 10+ -Tetraeder gema Èû 1 {[SSm 4/2 ] 4+ } das strukturelle Hauptmerkmal und sind nach Art einer dichtesten Stabpackung hexagonal gebu È ndelt. Der Ladungsausgleich und die dreidimensionale Vernetzung erfolgt u È ber zwei kristallographisch unterschiedliche Cl ± , die von jeweils drei Sm 3+ umgeben sind. Sm 2 SCl 4 : A Sulfide Chloride of trivalent Samarium with anti-SiS 2 -analogous Chains 1 {[SSm 4/2 ] 4+ } Abstract. Pale-yellow single crystals of the chloride-richest rare-earth(III) sulfide chloride known to date with the composition Sm 2 SCl 4 are obtained by the oxidation of samarium metal with sulfur in the molar ratio 2 : 3 in a melt of excess SmCl 3 at 850 °C (7 d) in evacuated silica ampoules. The crystal structure of Sm 2 SCl 4 (monoclinic, C2/c; a = 1519.8(1), b = 639.43(6), c = 702.18(7) pm, b = 98.057(8)°; Z = 4) exhibits Sm 3+ in eightfold anionic coordination of two S 2± and six Cl ± arranged as bicapped trigonal prisms. Anti-SiS 2 -analogous chains of trans-edge linked [SSm 4 ] 10+ tetrahedra ac-cording to 1 {[SSm 4/2 ] 4+ } running along [001] form the main structural feature and are hexagonally bundled as closest rod packing. Charge equalization and three-dimensional interconnection of these cationic chains occur via two crystallographically different Cl ± anions, each surrounded by three Sm 3+ .