Crystal architecture of R 2 SnS 5 ( R = Pr, Nd, Gd and Tb): crystal structure relationships in chalcogenides

The crystal structure of the R 2 SnS 5 ( R = Pr, Nd, Gd and Tb) compounds has been investigated using X-ray single-crystal diffraction. Crystal architecture and structural relationships among U 3 S 5 , Y 2 HfS 5 , R 2 SnS 5 compounds are discussed and a structural origin is determined. It is shown that the complex architecture of the crystal structure of Eu 5 Sn 3 S 12 is a result of interweaving of the simple crystal structures. The location of the copper ions in the non-stoichiometric compound Y 2 Cu 0.20 Sn 0.95 S 5 is proposed on the basis of comparative analysis of the R —S interatomic distances in the R 2 SnS 5 series of compounds.