Crystal structure of ∼RCu3S3 and ∼RCuTe2 (R=Gd–Lu) compounds

The crystal structures of ternary compounds TbCu3S3, Dy1.06Cu2.84S3 (space group R3-bar ), Ho0.67Cu2S2 (space group P3-bar m1), ErCu3S3 (space group P3-bar 1c), Yb0.80Cu1.60S2, Lu0.67Cu2S2, TbCuTe2, DyCuTe2, Tm1.07Cu0.78Te2, LuCuTe2 (space group P3-bar m1), Gd0.75Cu1.74Te2 (space group P3-bar 1m) were determined by means of X-ray single crystal diffraction. The S(Te) atoms are stacked in a close packed arrangement with the layers in the sequence AB. The R atoms are distributed over octahedral interstices whereas Cu atoms are located in tetrahedral interstices. Disorder of R and Cu atoms in studied chalcogenides is found. Crystal structure comparison showed that TbCuTe2 and DyCuTe2 crystallize as superstructure 2a×2a×2c to CaAl2Si2 structure type, whereas Gd0.75Cu1.74Te2, ErCu3S3 and TbCu3S3 (Dy1.06Cu2.84S3) have superstructure √3a×√3a×nc with n=1, 2, 3. - Graphical abstract: In the series of the ∼RCu3S3 and ∼RCuTe2 compounds the R and Cu atoms occupy disordered positions. The S(Te) atoms are stacked in a close packed arrangement with the layers in the sequence AB. Highlights: ► The ∼RCu3S3 and ∼RCuTe2 (R=Gd–Lu) crystallize with layered structure. ► Superstructure √3a×√3a×nc (n=1, 2, 3) to CaAl2Si2 structure type is found. ► TbCuTe2 and DyCuTe2 crystallize as superstructure 2a×2a×2c. ► Disorder of R and Cu atoms in studied chalcogenides is found.