Charge and structural ordering in the brownmillerite phases: La{sub 1-x}Sr{sub x}MnO{sub 2.5} (0.2<x<0.4)

Journal Article · Mon May 15 04:00:00 EDT 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.01.049· OSTI ID:20785000

Casey, Peter S ^[1]; Barker, Daniel ^[1]; Hayward, Michael A ^[1]

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1. Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR (United Kingdom)

The topotactic reduction of La{sub 1-x}Sr{sub x}MnO{sub 3} (0.2<x<0.4) perovskite phases to the corresponding La{sub 1-x}Sr{sub x}MnO{sub 2.5} brownmillerite phases with NaH is described. Neutron and electron diffraction data show the x=0.25 and 0.2 phases adopt structures with an unusual ordered L-R-L-R alternation of twisted chains of Mn(II) tetrahedra within each anion-deficient layer. This is accompanied by Mn(II)/(III) charge ordering within the remaining MnO{sub 6} octahedral layers. In contrast, the x=0.4 phase adopts a structure in which the twisted chains of tetrahedra are disordered.

• OSTI ID: 20785000
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 179; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ELECTRON DIFFRACTION
LANTHANUM COMPOUNDS
LAYERS
MANGANESE COMPOUNDS
NEUTRON DIFFRACTION
PEROVSKITE
REDUCTION
SODIUM HYDRIDES
STRONTIUM COMPOUNDS