Crystal structure of the RAgTe2 (R = Y, Tb, Dy, Ho and Er) compounds

The crystal structures of the RAgTe2 (R = Y, Tb, Dy, Ho and Er) compounds (space group P4¯21m, Pearson symbol tP8) were determined by means of X-ray powder diffraction: a = 0.71398(2) nm, c = 0.45947(2) nm, RI = 0.0701 (YAgTe2), a = 0.71466(3) nm, c = 0.46108(3) nm, RI = 0.0761 (TbAgTe2), a = 0.71287(3) nm, c = 0.45955(3) nm, RI = 0.0637 (DyAgTe2), a = 0.71033(3) nm, c = 0.45713(3) nm, RI = 0.0755 (HoAgTe2) and X-ray single crystal diffraction: a = 0.7091(1) nm, c =0.45650(9) nm, R1 = 0.0366 (ErAgTe2). The Te atoms in the structure of the RAgTe2 compounds are stacked in a close-packed arrangement with layers in the sequence AB. Half of the octahedral interstices are occupied by the R atoms. The Ag atoms are located in remaining octahedral interstices, but they are shifted from the centers of the respective octahedra and tetrahedral surrounding really exists for Ag.