Crystal structure of the R7CU3Te12 (R=Tb, Dy, Ho, Er and Tm) compounds

The crystal structures of the R7Cu3Te12 (R=Tb, Dy, Ho, Er and Tm) compounds (space group R3m, Pearson symbol hR27-5) were determined by means of X-ray single crystal diffraction: a = 0.43020(6) nm, c = 4.1720(8) nm, R-I = 0.0498 (Ho7Cu3Te12) and X-ray powder diffraction: a=0.43279(3)nm, c=4.1896(3)nm, R-I =0.0932 (Tb7Cu3Te12); a=0.43114(5)nm, c=4.1779(8)nm, R-I =0.0891 (DY7Cu3Te12); a=0.42802(2)nm, c=4.1575(2)nm, R-I =0.0849 (Er7Cu3Te12); a=0.42709(3)nm, c=4.1540(3)nm, R-I =0.0858 (Tm7Cu3Te12). The close packed Te layers in ...hhcc... stacking exists in the crystal structure of the R7Cu3Te12 (R = Tb, Dy, Ho, Er and Tm) compounds. The R atoms occupy 7/12 of octahedral interstices, whereas the Cu atoms occupy 1/8 of tetrahedral interstices. (c) 2005 Elsevier B.V. All rights reserved.