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X-Ray Reference Patterns and Structure of the Perovskite-Related Phase R2Cu9Ti12O36(R=Lanthanides)

Published

Author(s)

Winnie K. Wong-Ng, James A. Kaduk, J Suh

Abstract

The x-ray Rietveld refinement technique was used to determine the structure and prepare x-ray powder reference patterns forthe phases R2Cu9Ti 1 2036 (R = Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, Yb and Lu). R2Cu9Ti 1 2036 belongs to theperovskite-related [AC3](B4)012 family of structures, which are cubic with space group lm3. The lattice parameters of theR2Cu9Til 2036 series range from a = 7.37141(4) A, V= 400.55 A3 for R = Lu to a = 7.40065(2) A, and V = 405.33A3 for RNd. The trend of these lattice parameters parallels the lanthanide contraction'. In the structure R occupies the largericosahedral A site of the ideal AB03 perovskite structure, while Ti occupies the distorted octahedral B site. The Jahn-Tellercation Cu occupies the C site. The twelve oxygens surrounding Cu are arranged as three mutually-perpendicular rectangles ofdifferent size. The smallest and largest rectangles are nearly squares. One-third of the R site is vacant, and the chemicalformula can be written as [R2/3Xl/3Cu3l(Ti4)012, where X = vacancy. The x-ray powder patterns of R2Cu2Ti2O36 havebeen submitted to ICDD for inclusion in the Powder Diffraction File (PDF).
Citation
Powder Diffraction
Volume
20
Issue
3

Keywords

crystal chemistry, crystallography, Perovskite-related, powder diffraction file (PDF), R2Cu9Ti1203, Rietveld refinements, x-ray reference patterns

Citation

Wong-Ng, W. , A., J. and Suh, J. (2005), X-Ray Reference Patterns and Structure of the Perovskite-Related Phase R<sub>2</sub>Cu<sub>9</sub>Ti<sub>12</sub>O<sub>36</sub>(R=Lanthanides), Powder Diffraction (Accessed June 21, 2024)

Issues

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Created July 18, 2005, Updated February 19, 2017