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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/4027
Title: Crystal structures of Ln4Ni3O8 (Ln = La, Nd) triple layer T′-type nickelates
Authors: Poltavets V.V.
Lokshin K.A.
Croft M.
Mandal T.K.
Egami T.
Greenblatt M.
Published in: Inorganic Chemistry
Abstract: Single-phase Ln4Ni3O8 (Ln = La, Nd) nickelates were synthesized and their crystal structures were determined by Rietveld refinement of powder neutron diffraction data. The crystal structures of these mixed-valent Ni1+/Ni2+ phases belong to the T′-type and are built by intergrowth of LnO2 fluorite layers with triple NiO2 infinite-layer structural blocks. The major driving force of transformation of the LnO rock-salt block of the parent Ln 4Ni3O10-δ Ruddlesden-Popper phases to the fluorite arrangement in the reduced Ln4Ni3O8 phases is attributed to internal structural stress. This transformation allows longer Ni-O bonds in Ln4Ni3O8 without overstretching of the Ln-O bonds, especially in the equatorial plane. The observed displacement of Ni atoms from the outer NiO2 planes toward the Ni atom of the central NiO2 plane in Ln4Ni 3O8 is ascribed to large electrostatic repulsion from the fluorite part of the structure. X-ray absorption spectra near the K-edge of Ni suggest that the charge density on the nickel ion is similar for all members of the T′-type Lnn+1NinO2n+2 homologous series, which correlates with nearly constant Ni-O bond lengths observed in all the reduced nickelates. This suggests that the formal changes in the valence state of Ni affect the covalency of the Ni-O bond. © 2007 American Chemical Society.
Citation: Inorganic Chemistry (2007), 46(25): 10887-10891
URI: https://doi.org/10.1021/ic701480v
http://repository.iitr.ac.in/handle/123456789/4027
Issue Date: 2007
ISSN: 201669
Author Scopus IDs: 7004054790
6602086888
56242957000
57200780613
7101774365
7102535684
Author Affiliations: Poltavets, V.V., Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, United States
Lokshin, K.A., Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, United States
Croft, M., Department of Physics and Astronomy, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, United States, Brookhaven National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, United States
Mandal, T.K., Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, United States
Egami, T., Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, United States, Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States
Greenblatt, M., Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, United States
Corresponding Author: Greenblatt, M.; Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, United States; email: martha@rutchem.rutgers.edu
Appears in Collections:Journal Publications [CY]

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