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The X-ray diffraction powder patterns were prepared and the crystal structures were refined for the double-perovskite series of compounds, Sr2RSbO6 (R = Pr, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, Yb, and Lu). We found the structures of the entire Sr2RSbO6 series to be monoclinic with space group P21/n (no. 14), and Z = 2. From R = Lu to Pr, the lattice parameters “a” range from 5.7779(2) to 5.879 05(8) Å, “b” range from 5.7888(2) to 5.969 52(9) Å, “c” range from 8.1767(3) to 8.369 20(12) Å, “β” range from 90.112(2)° to 90.313(1)°, and “V” range from 273.483(4) to 293.714(7) Å3. These lattice parameters follow the well-established trend of “lanthanide contraction”. The R3+ and Sb5+ ions are found to be fully ordered in the double-perovskite arrangement of alternating corner-sharing octahedra in a zigzag fashion. The SrO12, RO6, and SbO6 cages are all found to have distorted coordination environments. Powder diffraction patterns of these compounds have been prepared, submitted, and published in the Powder Diffraction File.

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Copper I 7400 Crystal Chemistry and Crystallography of the SrLn 2 CuO 5 (Ln: Lanthanides) Phases. -The title compounds are prepared by sintering of compacted powder mixtures of SrCO3, Ln2O3, and CuO in air (1. 850°C, 2 d; 2. 950°C, 9 d). The samples are characterized by powder XRD. Stable SrLn2CuO5 phases are formed only for Ln: Dy and Ho. The compounds crystallize in the orthorhombic space group Pnma with Z = 8 and are isostructural with the "green phase", BaLn 2 CuO 5 . The structure contains monocapped trigonal LnO7 prisms and distorted square pyramidal CuO5 units. -(WONG-NG*, W.; HAUGAN, T.; KADUK, J. A.; YOUNG, R. A.; YANG, Z.; JANG, M. H.; LUONG, M.; J. Solid State