Structure solution of Pb13Mn9O25 by electron crystallography

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Pb13Mn9O25, a complex oxide solved from transmission electron microscopy data

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Ultramicroscopy 110 (2010) 881–890 Published in:

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Problem to solve New unknown compound in multiple phased sample All phases perovskite based Peaks overlap in X-ray data, so no solution from that

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So we turn to the transmission electron microscope...

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Electron diffraction gives us the cell parameters and space group.

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a=b=14.2 Å=ap√13 c=3.9 Å=ap P4/m

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EELS and EDX give us the composition.

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Pb13Mn9O5

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We collect the intensities of the reflections from precession electron diffraction data.

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We feed the intensities and all collected data to direct methods (SIR2008)

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Pb Mn Out comes a solution for the cation positions. Mn-vacancy

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Pb Mn There are ordered manganese vacancies. Mn-vacancy

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But where is the oxygen? ???

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HAADF-STEM confirms that Mn is missing, but gives no info on oxygen

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We find the oxygen with a global optimization in direct space (FOX) using the output from direct methods as input.

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Structure is solved with ... two solutions !?

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E = -7.42 eV E = -11.1 eV Structure optimisation favors one model

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The calculated images for this model agree well with the experimental HREM images

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Joke Hadermann, Artem M. Abakumov, Alexander A. Tsirlin, Mauro Gemmi, Hans D’Hondt, Vladimir P.Filonenko, Julie Gonnissen, Haiyan Tan, Johan Verbeeck, HelgeRosner, EvgenyV.Antipov All precise details and data can be found in the publication Ultramicroscopy 110 (2010) 881–890 by the authors Direct space structure solution from precession electron diffraction data: Resolving heavy and light scatterers in Pb13Mn9O25