SYNTHESIS AND STRUCTURAL-ANALYSIS OF SR5.8LA4.4TI7.8S24O4 AND LA14TI8S33O4 - 2 NEW OXYSULFIDES CONTAINING A COMMON (2)(INFINITY)[(TI4S2O4)(TIS6)(4 2)](12-) LAYER/

Two new titanium oxysulfides Sr5.8La4.4Ti7.8S24O4 and La14Ti8S33O4 wer e prepared by high-temperature methods (925-950 degrees C; similar to 90-104 h) from stoichiometric ratios of SrS, La2S3, Ti, S, and TiO2 or La2O3 (or SrO for Sr(5.8)La(4.4)Ti(7.8)Sa(24)O(4)) oxygen sources. Th e sample crystallinity and purity was greatly enhanced when LaCl3 flux es were employed. The compounds were characterized by single-crystal a nd powder (Rietveld profile analysis) X-ray diffraction studies and ED X analysis. Both compounds are black insulators (all Ti4+) and contain a common (2)(infinity)[(Ti4S2O4)(TiS6)(4/2)](-12) layer despite the d ifference in composition and crystal symmetry. For La14Ti8S33O4, these layers are separated by TiS6 octahedra and 8 and 9-coordinate La-S po lyhedra. For Sr5.8La4.4Ti7.8S24O4, the layers are separated by a TiS6 octahedron and two disordered Ti1-xSrxS6 octahedra. La and Sr are also disordered on an interlayer nine-coordinate site. Crystal data (153 K ): Sr5.8La4.4Ti7.8S24O4, tetragonal, space group P4/mmm a = 10.569(3), c = 8.516(4) Angstrom, V = 951.4(5) Angstrom(3), Z = 1, R(F) = 4.28%, and R(w)(F-2) = 10.39%. For La14Ti8S33O4, monoclinic, space group C2/ m, a = 14.904(1), b = 14.736(1), c = 12.278(1) Angstrom, beta = 112.77 3(5)degrees, V = 2486.2(3) Angstrom(3), Z = 2, R(F) = 3.92%, and R(w)( F-2) = 10.00%.