Crystal structures of the compounds RCuS2 (RÂ =Â Dy, Ho, Yb, Lu) and Tm0.97Cu1.10S2

The crystal structures of the compounds RCuS2 (R = Dy, Ho, Yb, Lu) and Tm0.97Cu1.10S2 (space group P212121) were investigated using X-ray powder diffraction: a = 0.62532(6) nm, b = 1.3375(1) nm, c = 0.39641(1) nm, Pearson symbol oP16, RI = 0.0765 (for DuCuS2); a = 0.62497(3) nm, b = 1.33282(5) nm, c = 0.39525(1) nm, Pearson symbol oP16, RI = 0.0743 (for HoCuS2); a = 0.62171(3) nm, b = 1.31388(5) nm, c = 0.39062(1) nm, Pearson symbol oP16, RI = 0.0768 (for YbCuS2); a = 0.62395(9) nm, b = 1.3146(2) nm, c = 0.39060(4) nm, Pearson symbol oP16 (for LuCuS2) and a = 0.62255(4) nm, b = 1.31934(7) nm, c = 0.39195(2) nm, Pearson symbol oP16.27, RI = 0.0812 (for Tm0.97Cu1.10S2). The S atoms of the compounds RCuS2 (R = Dy, Ho, Yb, Lu) and Tm0.97Cu1.10S2 are stacked in a close-packed arrangement with layers in the sequence AB. Half of the octahedral interstices are occupied by R (or Tm) atoms in the structures of all compounds. The remaining octahedral interstices are occupied by Cu2 atoms only in the structure of the Tm0.97Cu1.10S2 compound. The Cu and Cu1 atoms are located in one quart of the tetrahedral interstices of the RCuS2 (R = Dy, Ho, Yb, Lu) and Tm0.97Cu1.10S2 compounds, respectively.