Additional oxygen ordering in La[sub 2]NiO[sub 4. 25]' (La[sub 8]Ni[sub 4]O[sub 17]). II. Structural features

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1293· OSTI ID:5155625

Demourgues, A; Weill, F; Darriet, B; Wattiaux, A; Grenier, J C; Gravereau, P; Pouchard, M ^[1]

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1. Universite de Bordeaux I, Talence (France)

On the basis of data obtained from the refinement of neutron diffraction experiments, the structural features of La[sub 8]Ni[sub 4]O[sub 17] ( LaNiO[sub 4.25']) are discussed. It is shown that the additional oxygen atoms in the La[sub 2]O[sub 2] layers form (O[sup 5[minus]][sub 3]) polyoxides including one delocalized hole. In the NiO[sub 2] planes, a periodic modulation of the equatorial Ni-O distances characterizes various electronic configurations of the nickel cations and a 2D charge density wave occurs, which is more pronounced at low temperature than at room temperature. A strong coupling between the (O[sup 5[minus]][sub 3]) polyoxides and the NiO[sub 2] planes results from charge transfer mechanisms, which also account for the stabilization of monovalent nickel Ni[sup +] in this compound. The formation of -Ni[sup +]-(O[sup 5][minus])-chains along given [111][sub T] direction is correlated to the interstitial oxygen ordering previously evidenced.

• OSTI ID: 5155625
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 106:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMISTRY
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTROCHEMISTRY
ELECTRON MICROSCOPY
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LATTICE PARAMETERS
MICROSCOPY
MONOCLINIC LATTICES
NICKEL COMPOUNDS
NICKEL OXIDES
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY