Anhydrous sulfates of rare earth elements: Syntheses and crystal structures of Y-2(SO4)(3) and Sc-2(SO4)(3)

The reaction of YCl3 and Li2SO4 in sealed gold ampoules yields colorless si ngle crystals of Y-2(SO4)(3). According to the X-ray single crystal determi nation the compound crystallizes with orthorhombic symmetry (Pbcn, Z = 4, a = 1273.97(13), b = 916.76(9), c = 926.08(7) pm, R-all = 0.0274). The cryst al structure is buildt up from [YO6] octahedra and sulfate tetrahedra conne cted via all vertices. In the same way [ScO6] octahedra and sulfate groups are connected in the crystal structure of SC2(SO4)(3) (trigonal, R-3, Z = 6 , a = 870.7(1), c = 2247.0(4) pm, R-all = 0.0255). Single crystals of Sc-2( SO4)(3) were obtained via crystallisation of powder samples from a NaCl mel t. The crystal structures of both compounds are closely related to each oth er and to the binary sulfides Rh2S3 and Lu2S3; the structures are the same with the complex SO42- ions replacing the S2- ions of the sulfides.