skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A-site cation ordering in AA'BB'O{sub 6} perovskites

Abstract

Unlike ordering of the octahedral B-site cations, ordering of the larger A-site cations in stoichiometric perovskites is rare. Herein the A- and B-site ordering characteristics of several double perovskites with AA'BB'O{sub 6} stoichiometry have been investigated. The compounds investigated include NaLaMgWO{sub 6}, NaLaMgTeO{sub 6}, NaLaScNbO{sub 6}, NaLaScSbO{sub 6}, NaLaTi{sub 2}O{sub 6}, and NaLaZr{sub 2}O{sub 6}. Group theoretical methods are used to enumerate the possible structures of AA'BB'X{sub 6} double perovskites that result from the combination of rock salt ordering of the B-site cations, layered ordering of the A-site cations, and octahedral tilting distortions. This combination results in 12 possible structures in addition to the aristotype. Among the compounds investigated only NaLaMgWO{sub 6} and NaLaScNbO{sub 6} show significant long-range ordering of the A-site cations, Na{sup +} and La{sup 3+}. A complete structural characterization is presented for NaLaMgWO{sub 6}. This compound possesses monoclinic C2/m (12) space group symmetry, with unit cell dimensions of a=7.8074(1)A, b=7.8158(1)A, c=7.8977(1)A, {beta}=90.136(1){sup o} at room temperature. The results presented here show that in AA'BB'O{sub 6} perovskites layered ordering of A-site cations creates a bonding instability that is compensated for by a second-order Jahn-Teller distortion of the B' cation. These two distortions are synergistic and the removal ofmore » one leads to the disappearance of the other.« less

Authors:
 [1];  [2]
  1. Ohio State University, Department of Chemistry, 100 West 18th Avenue, Columbus, OH 43210-1185 (United States)
  2. Ohio State University, Department of Chemistry, 100 West 18th Avenue, Columbus, OH 43210-1185 (United States). E-mail: mknapp@chemistry.ohio-state.edu
Publication Date:
OSTI Identifier:
20784959
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 179; Journal Issue: 4; Other Information: DOI: 10.1016/j.jssc.2006.01.005; PII: S0022-4596(06)00012-0; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; LANTHANUM IONS; LATTICE PARAMETERS; MONOCLINIC LATTICES; OXIDES; PEROVSKITES; SODIUM IONS; SPACE GROUPS; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION

Citation Formats

Knapp, Meghan C., and Woodward, Patrick M. A-site cation ordering in AA'BB'O{sub 6} perovskites. United States: N. p., 2006. Web. doi:10.1016/j.jssc.2006.01.005.
Knapp, Meghan C., & Woodward, Patrick M. A-site cation ordering in AA'BB'O{sub 6} perovskites. United States. doi:10.1016/j.jssc.2006.01.005.
Knapp, Meghan C., and Woodward, Patrick M. Sat . "A-site cation ordering in AA'BB'O{sub 6} perovskites". United States. doi:10.1016/j.jssc.2006.01.005.
@article{osti_20784959,
title = {A-site cation ordering in AA'BB'O{sub 6} perovskites},
author = {Knapp, Meghan C. and Woodward, Patrick M.},
abstractNote = {Unlike ordering of the octahedral B-site cations, ordering of the larger A-site cations in stoichiometric perovskites is rare. Herein the A- and B-site ordering characteristics of several double perovskites with AA'BB'O{sub 6} stoichiometry have been investigated. The compounds investigated include NaLaMgWO{sub 6}, NaLaMgTeO{sub 6}, NaLaScNbO{sub 6}, NaLaScSbO{sub 6}, NaLaTi{sub 2}O{sub 6}, and NaLaZr{sub 2}O{sub 6}. Group theoretical methods are used to enumerate the possible structures of AA'BB'X{sub 6} double perovskites that result from the combination of rock salt ordering of the B-site cations, layered ordering of the A-site cations, and octahedral tilting distortions. This combination results in 12 possible structures in addition to the aristotype. Among the compounds investigated only NaLaMgWO{sub 6} and NaLaScNbO{sub 6} show significant long-range ordering of the A-site cations, Na{sup +} and La{sup 3+}. A complete structural characterization is presented for NaLaMgWO{sub 6}. This compound possesses monoclinic C2/m (12) space group symmetry, with unit cell dimensions of a=7.8074(1)A, b=7.8158(1)A, c=7.8977(1)A, {beta}=90.136(1){sup o} at room temperature. The results presented here show that in AA'BB'O{sub 6} perovskites layered ordering of A-site cations creates a bonding instability that is compensated for by a second-order Jahn-Teller distortion of the B' cation. These two distortions are synergistic and the removal of one leads to the disappearance of the other.},
doi = {10.1016/j.jssc.2006.01.005},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = 4,
volume = 179,
place = {United States},
year = {2006},
month = {4}
}