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Title
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Tetrahedral chain order in the brownmillerite
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Author
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Abstract
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| The crystal structure of the Sr2Fe2O5 brownmillerite has been investigated using electron diffraction and high resolution electron microscopy. The Sr2Fe2O5 structure demonstrates two-dimensional order: the tetrahedral chains with two mirror-related configurations (L and R) are arranged within the tetrahedral layers according to the −L−R−L−R− sequence, and the layers themselves are displaced with respect to each other over 1/2[111] or 1/2[11] vectors of the brownmillerite unit cell, resulting in different ordered stacking variants. A unified superspace model is constructed for ordered stacking sequences in brownmillerites based on the average brownmillerite structure with a = 5.5298(4)Å, b = 15.5875(12)Å, c = 5.6687(4)Å, and (3 + 1)-dimensional superspace group I2/m(0βγ)0s, q = βb* + γc*, 0 ≤ β ≤ 1/2, 0 ≤ γ ≤ 1. |
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Language
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Dutch
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Source (journal)
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Chemistry of materials / American Chemical Society. - Washington, D.C., 1989, currens
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Publication
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Washington, D.C.
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2008
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ISSN
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0897-4756
[print]
1520-5002
[online]
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DOI
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10.1021/CM801723B
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Volume/pages
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20
:22
(2008)
, p. 7188-7194
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ISI
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000261002200039
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Full text (Publisher's DOI)
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