Synchrotron X-ray Diffraction Study of Double Perovskites Sr2RNbO6 (R=Sm, Gd, Dy, Ho, Y, Tm, and Lu)

Published

December 7, 2018

Author(s)

Winnie K. Wong-Ng, James A. Kaduk, Shailee P. Diwanji

Abstract

A series of double-perovskite oxides, Sr2RNbO6 (R= Sm, Gd, Dy, Ho, Y, Tm, and Lu) were synthesized and their crystal structure and powder diffraction reference patterns were determined using the Rietveld analysis technique. The R= Gd, Ho, and Lu samples were studied using synchrotron radiation while R= Sm, Dy, Y, and Tm samples were studied using laboratory X-ray diffraction. Members of Sr2RNbO6 are monoclinic with a space group of P21/n and are isostructural with each other. Following the trend of ‘lanthanide contraction’, from R=Sm to Lu, the lattice parameters ‘a’ of these compounds decreases from 5.84697(9) Å to 5.78151(4) Å, b from 5.93168(12) Å to 5.81030(3) Å, c from 8.32095(11) Å to 8.19022(6) Å, and V decreases from 288.512 (7) Å3 to 275.128 (2) Å3. In this double perovskite series, the R3+ and Nb5+ ions are structurally ordered. The average Nb-O bond length is nearly constant, while the average R-O bond length decreases with the decreasing ionic radius of R3+. Powder diffraction patterns for these compounds have been submitted to the Powder Diffraction File (PDF).

Citation

Powder Diffraction

Volume

33

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1017/S0885715618000593

Keywords

Sr2RNbO6, Synchrotron X-ray diffraction patterns, Powder Diffraction File (PDF), double perovskites

Citation

Wong-Ng, W. , Kaduk, J. and Diwanji, S. (2018), Synchrotron X-ray Diffraction Study of Double Perovskites Sr2RNbO6 (R=Sm, Gd, Dy, Ho, Y, Tm, and Lu), Powder Diffraction, [online], https://doi.org/10.1017/S0885715618000593 (Accessed December 14, 2024)