Synthesis, characterization, and magnetic properties of new Rh(III) compounds with the K4CdCl6 structure-type:: Sr3MRhO6 (M = Sm, Eu, Tb, Dy, Ho, Er, and Vb)

The compounds Sr3MRhO6 (M = Sm, Eu, Tb, Dy, Ho, Er, and Yb) have been synthesized and structurally characterized by Rietveld refinement of powder X-ray diffraction data in the space group R (3) over bar c; Z = 6. The lattice parameters for the series were found to be a = 9.78570(7) and c = 11.4811(1) Angstrom, a = 9.7837(1) and c = 11.4421(2) Angstrom, a = 9.7662(2) and c = 11.3812(4) Angstrom, a = 9.7627(2) and c = 11.3451(2) Angstrom, a = 9.7591(2) and c = 11.3159(2) Angstrom, a = 9.7557(2) and c = 11.2919(3) Angstrom, and a = 9.7390(2) and c = 11.2501(3) Angstrom, for Sr3SmRhO6, Sr3EuRhO6, Sr3TbRhO6, Sr3DyRhO6, Sr3HoRhO6, Sr3ErRhO6, and Sr3YbRhO6, respectively. These compounds are isostructural with K4CdCl6. The structure consists of infinite one-dimensional chains of alternating face-shared RhO6 octahedra and MO6 trigonal prisms (M= Sm, Eu, Tb, Dy, Ho, Er, and Yb). The strontium cations are located in a distorted square antiprismatic environment. Magnetic susceptibility data for the compounds Sr3MRhO6 (M = Tb, Dy, Ho, Er, and Yb) obey the Curie law, with the expected mu(eff) values consistent with an oxidation state of +3 for both Rh and M. (C) 1998 Academic Press.