X-ray diffraction study of phases in the system CaS-Lu2S 3 (0-50 mol % Lu2S3)

Thirteen samples were synthesized in the system CaS-Lu2S 3 in the range 0-50 mol % Lu2S3 and studied by X-ray powder diffraction (phase analysis, determination and refinement of unit cell parameters, Rietveld structure refinement). The phases crystallizing in the system have NaCl-type structures (space group Fm3m, unit cell parameter a 0) with a cubic, hexagonal, or orthorhombic superstructure, the respective structure types being Yb0.875S (space group F 4¯ 3m, a ∼ 2a 0), CaY2Se4 (space group R 3¯m, a ∼ a 0 √2, c ∼ 2a 0 √3), and Tm 0.76Se (space group Pnnn; a ∼ a 0 √2, b ∼ a 0 √2, c ∼ 2a 0), and a phase with a Yb 3S4-type orthorhombic unit cell (space group Pnma). © 2008 MAIK Nauka.