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Title
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Direct space structure solution from precession electron diffraction data: resolving heavy and light scatterers in
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Author
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Abstract
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| The crystal structure of a novel compound Pb13Mn9O25 has been determined through a direct space structure solution with a Monte-Carlo-based global optimization using precession electron diffraction data (a=14.177(3) Å, c=3.9320(7) Å, SG P4/m, RF=0.239) and compositional information obtained from energy dispersive X-ray analysis and electron energy loss spectroscopy. This allowed to obtain a reliable structural model even despite the simultaneous presence of both heavy (Pb) and light (O) scattering elements and to validate the accuracy of the electron diffraction-based structure refinement. This provides an important benchmark for further studies of complex structural problems with electron diffraction techniques. Pb13Mn9O25 has an anion- and cation-deficient perovskite-based structure with the A-positions filled by the Pb atoms and 9/13 of the B positions filled by the Mn atoms in an ordered manner. MnO6 octahedra and MnO5 tetragonal pyramids form a network by sharing common corners. Tunnels are formed in the network due to an ordered arrangement of vacancies at the B-sublattice. These tunnels provide sufficient space for localization of the lone 6s2 electron pairs of the Pb2+ cations, suggested as the driving force for the structural difference between Pb13Mn9O25 and the manganites of alkali-earth elements with similar compositions. |
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Language
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English
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Source (journal)
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Ultramicroscopy. - Amsterdam
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Publication
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Amsterdam
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2010
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ISSN
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0304-3991
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DOI
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10.1016/J.ULTRAMIC.2010.03.012
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Volume/pages
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110
:7
(2010)
, p. 881-890
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ISI
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000280050900023
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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