X-ray structure analyses for single crystals of A- and C-type Ce2S3

Dark red, lath-shaped single crystals of A-type Ce2S3 (orthorhombic, Pnma, a = 753.23(6), b = 409.67(3), c = 1572.76(9) pm, V-m = 73.065(8) cm(3)/mol, Z = 4) are obtained along with deep red, bead-shaped single crystals of C- type Ce2S3 (cubic, I (4) over bar 3d, a = 865.24(5) pm, V-m = 73.140(7) cm( 3)/mol, Z = 5.333) and cinnabar (alpha-HgS) during unsuccessful efforts to synthesize HgCe2S4 by the oxidation of mercury and cerium metal with sulfur (molar ratio 1:2:4) in evacuated silica tubes at 400 degrees C in the pres ence of a fluxing KCl-LiCl mixture within seven days. Their crystal structu res belong to the alpha-Gd2S3- (A type) or a cation-deficient Th3P4-type fa mily (C type) according to M(2.667)square(0.333)S(4) (Z = 4) or M2S3 (Z = 5 .333), respectively, offering coordination numbers of seven and eight (S2- arranged as mono- or bicapped trigonal prisms in A-Ce2S3) or eight only (S2 - arranged as trigonal dodecahedra in C-Ce2S3) to the Ce3+ cations.