Oxygen vacancies in pyrochlore oxides: Powder neutron diffraction study of Pb{sub 2}Ir{sub 2}O{sub 6.5} and Bi{sub 2}Ir{sub 2}O{sub 7-y}
- Univ. of Sydney (Australia)
The structure of the oxygen deficient pyrochlores Bi{sub 2}Ir{sub 2}O{sub 7-y} and Pb{sub 2}Ir{sub 2}O{sub 6.5} were refind by Rietveld analysis of time-of-flight neutron powder diffraction data. The diffraction data for Pb{sub 2}Ir{sub 2}O{sub 6.5} have been used to refine the structure in the cubic space group F43m, {alpha}=10.26450(4) {Angstrom} in which there is oxygen vacancy ordering and where each Pb atom is displaced 0.04 {Angstrom} was fitted within space group Fd3m, {alpha}=10.3256(1) {Angstrom} in which the oxygen vacancies are randomly distributed over the O{sup {prime}} sites. In both structures the Ir atoms are in a nearly regular octahedral coordination whereas the Bi and Pb cations have a distorted eightfold coordination, compressed scalehedron, geometry. XPS studies indicate there is appreciable surface enrichment of the A cation.
- OSTI ID:
- 274257
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 123; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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