Synthesis and Structural Analysis of Bi0.5La13.5Ti8S29Cl4O4 and La23.1Ti16.2S49Cl8O8: Two New Oxychlorosulfide Compounds with 2[(Ti4Q2O4)(TiQ6)4/2] Layers Where Q=S/Cl

Two new titanium oxychlorosulfide compounds, Bi0.5La13.5Ti8S29Cl4O4 and La23.1Ti16.2S49Cl8O8, were prepared from the elements and binaries (oxides and sulfides) at 950° C in evacuated quartz tubes in the presence of LaCl3 flux. The compositions of the compounds were determined by wavelength dispersive X-ray analysis and single crystal X-ray diffraction. Both compounds have 2[(Ti4Q2O4)(TiQ6)4/2] oxysulfide layers (OS) that are separated by oxide-free Ti–Q layers (Q=S, Cl solid solution). For Bi0.5La13.5Ti8S29Cl4O4, the oxysulfide layers are separated by [La6Ti2Q19] layers containing isolated, distorted TiQ6 octahedra. La23.1Ti16.2S49Cl8O8 has [La4.1Ti4.9Q20] (A) and [La6Ti2.19Q19] (B) layers that alternatively stack with the oxysulfide layers along the c-axis following the sequence –A–OS–B–OS–A–OS–B–. The chloride ions could not be crystallographically differentiated from the sulfide ions. Crystal data for Bi0.5La13.5Ti8S29Cl4O4: orthorhombic, Cmcm, a=14.7463(9) ?, b=14.9009(8) ?, c=22.680(4) ?, V=4983.5(10) ?3, Z=4, T=153(2) K, R1(F)=4.17%, wR2(F2)=8.80% for all 2352 unique reflections. For La23.1Ti16.2S49Cl8O8: monoclinic, C2/m, a=14.8278(4) ?, b=14.7241(3) ?, c= 20.2724(6) ?, BETA=103.54(1)°, V=4302.9(2) ?3, Z=2, T=153(2), R1(F)=4.94%, wR2(F2)= 12.00% for all 3952 unique reflections.