SYNTHESIS AND CRYSTAL STRUCTURE OF CsLnZnS 3 (Ln = Gd, Dy)

CsLnZnS 3 (Ln = Gd, Dy) crystals are obtained by the interaction of metal sulfides in the cesium iodide melt. It is found that these compounds are isostructural, belong to the KCuZrS 3 structure type, and crystallize in the space group Cmcm with the parameters a = 4.010(5) Å, b = 15.32(3) Å, c = 10.542(19) Å for CsGdZnS 3 and a = 4.0106(3) Å, b = 15.2493(12) Å, c = 10.5978(8) Å for CsDyZnS 3 . The structures of these compounds consist of {LnS 6 } octahedra and {ZnS 4 } tetrahedra, which by sharing edges, form charged 2∞ {LnZnS 3 } – layers separated by Cs + ions. Band gaps of these compounds are determined as 3.70 eV and 3.84 eV for CsGdZnS 3 and CsDyZnS 3 respectively.