CRYSTAL-STRUCTURE REFINEMENT OF BACU2S2 TETRAGONAL MODIFICATION

Powder samples of BaCu2S2 tetragonal modification have been investigation on DRON-UM1 (R = 192 mm, CuK-alpha-radiation). Crystallographic data: a = 3,906 (1), c = 12,653 (3) A-degrees, sp. gr. 14/mmm, V = 193,01 A-degrees-3, Z = 2, D(x) = 5,653 g/sm3. The crystal structure has been refined to R = 3,5 %: Ba (0, 0, 0) Cu (0,5, 0, 0,25), S (0, 0, 0,363). The CuS4-tetrahedra form continuous layers separated through Ba atoms. The distances are: Cu-S 2,394, Ba-S 3,285, Cu-Cu 2,762 A-degrees. The tetragonal form of BaCu2S2 is more compact against the orthorhombic one.