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Title: The synthesis and complex anion-vacancy ordered structure of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}

Abstract

The low-temperature topotactic reduction of La{sub 0.33}Sr{sub 0.67}MnO{sub 3} with NaH results in the formation of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}. A combination of neutron powder and electron diffraction data show that La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42} adopts a novel anion-vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the 'octahedral' and tetrahedral layers (Pcmb, a=5.5804(1) A, b=23.4104(7) A, c=11.2441(3) A). A significant concentration of anion vacancies at the anion site, which links neighbouring 'octahedral' layers means that only 25% of the 'octahedral' manganese coordination sites actually have 6-fold MnO{sub 6} coordination, the remainder being MnO{sub 5} square-based pyramidal sites. The chains of cooperatively twisted apex-linked MnO{sub 4} tetrahedra adopt an ordered -L-R-L-R- arrangement within each tetrahedral layer. This is the first published example of a fully refined structure of this type which exhibits such intralayer ordering of the twisted tetrahedral chains. The rationale behind the contrasting structures of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42} and other previously reported reduced La{sub 1-x}Sr{sub x}MnO{sub 3-y} phases is discussed. - Graphical Abstract: The topotactic reduction of the perovskite phase La{sub 0.33}Sr{sub 0.67}MnO{sub 3} with NaH yields La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42(3)}, which adopts a novel anion vacancy ordered structure with a 6-layer OOTOOT' stacking sequence ofmore » the 'octahedral' and tetrahedral layers. The anion site that links the neighbouring octahedral layers is partially occupied so only 25% of the 'octahedral' manganese sites actually have 6-fold MnO{sub 6} coordination. Highlights: > Topotactic reduction with NaH to form a mixed valent Mn{sup 2+}/Mn{sup 3+} phase. > Novel layered anion-vacancy ordered structure. > Comparison to related brownmillerite structure types.« less

Authors:
 [1];  [2];  [1]
  1. Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)
  2. EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)
Publication Date:
OSTI Identifier:
21580152
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 184; Journal Issue: 7; Other Information: DOI: 10.1016/j.jssc.2011.05.026; PII: S0022-4596(11)00275-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; COMPARATIVE EVALUATIONS; COMPLEXES; ELECTRON DIFFRACTION; LAYERS; MANGANESE; MANGANESE IONS; MANGANESE OXIDES; PERMANGANATES; PEROVSKITE; SYNTHESIS; TEMPERATURE RANGE 0065-0273 K; VACANCIES; CHALCOGENIDES; CHARGED PARTICLES; COHERENT SCATTERING; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; DIFFRACTION; ELEMENTS; EVALUATION; IONS; MANGANESE COMPOUNDS; METALS; MINERALS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PEROVSKITES; POINT DEFECTS; SCATTERING; TEMPERATURE RANGE; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS

Citation Formats

Dixon, Edward, Hadermann, Joke, and Hayward, Michael A., E-mail: michael.hayward@chem.ox.ac.uk. The synthesis and complex anion-vacancy ordered structure of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}. United States: N. p., 2011. Web. doi:10.1016/j.jssc.2011.05.026.
Dixon, Edward, Hadermann, Joke, & Hayward, Michael A., E-mail: michael.hayward@chem.ox.ac.uk. The synthesis and complex anion-vacancy ordered structure of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}. United States. doi:10.1016/j.jssc.2011.05.026.
Dixon, Edward, Hadermann, Joke, and Hayward, Michael A., E-mail: michael.hayward@chem.ox.ac.uk. Fri . "The synthesis and complex anion-vacancy ordered structure of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}". United States. doi:10.1016/j.jssc.2011.05.026.
@article{osti_21580152,
title = {The synthesis and complex anion-vacancy ordered structure of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}},
author = {Dixon, Edward and Hadermann, Joke and Hayward, Michael A., E-mail: michael.hayward@chem.ox.ac.uk},
abstractNote = {The low-temperature topotactic reduction of La{sub 0.33}Sr{sub 0.67}MnO{sub 3} with NaH results in the formation of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42}. A combination of neutron powder and electron diffraction data show that La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42} adopts a novel anion-vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the 'octahedral' and tetrahedral layers (Pcmb, a=5.5804(1) A, b=23.4104(7) A, c=11.2441(3) A). A significant concentration of anion vacancies at the anion site, which links neighbouring 'octahedral' layers means that only 25% of the 'octahedral' manganese coordination sites actually have 6-fold MnO{sub 6} coordination, the remainder being MnO{sub 5} square-based pyramidal sites. The chains of cooperatively twisted apex-linked MnO{sub 4} tetrahedra adopt an ordered -L-R-L-R- arrangement within each tetrahedral layer. This is the first published example of a fully refined structure of this type which exhibits such intralayer ordering of the twisted tetrahedral chains. The rationale behind the contrasting structures of La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42} and other previously reported reduced La{sub 1-x}Sr{sub x}MnO{sub 3-y} phases is discussed. - Graphical Abstract: The topotactic reduction of the perovskite phase La{sub 0.33}Sr{sub 0.67}MnO{sub 3} with NaH yields La{sub 0.33}Sr{sub 0.67}MnO{sub 2.42(3)}, which adopts a novel anion vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the 'octahedral' and tetrahedral layers. The anion site that links the neighbouring octahedral layers is partially occupied so only 25% of the 'octahedral' manganese sites actually have 6-fold MnO{sub 6} coordination. Highlights: > Topotactic reduction with NaH to form a mixed valent Mn{sup 2+}/Mn{sup 3+} phase. > Novel layered anion-vacancy ordered structure. > Comparison to related brownmillerite structure types.},
doi = {10.1016/j.jssc.2011.05.026},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = 7,
volume = 184,
place = {United States},
year = {2011},
month = {7}
}