Syntheses, structures and properties of some osmates(IV,V) adopting the pyrochlore and weberite structures
Syntheses, structures and properties of some osmates(IV,V) adopting the pyrochlore and weberite structures
Samples of the complex osmates CaOs2O7, Tl2Os2O7 - (x) and Pb2Os2O7 - (x) have been obtained by direct reaction of the component oxides in sealed tubes. The structures and compositions of these materials have been investigated by powder neutron and X-ray diffraction at room temperature and through variable temperature studies. Ca2Os2O7 adopts a stoichiometric, orthorhombic weberite structure but the distortion of the OsO6 octahedra and eightfold Ca-O co-ordinations decrease with increasing temperature indicating that this material lies close to the weberite/pyroch lore phase boundary. The lead and thallium phases adopt oxygen deficient, cubic pyrochlore structures under the synthesis conditions employed though no evidence was found of cation non-stoichiometry. Preliminary measurements of the electronic properties of weberite Ca2Os2O7 are also reported and discussed in comparison with the lead, thallium, cadmium and mercury osmate pyrochlores.
high-pressure synthesis, neutron-diffraction, metal, transition, cd2os2o7, oxide
2376-2382
Reading, J.
40adb8ac-65ba-4b9c-82da-fd51ee2f7964
Knee, C.S.
d241249a-3d10-4b3e-9931-e3dd1029bb30
Weller, M.T.
36a60b56-049f-466c-a1d7-39d6b0d85ff4
2002
Reading, J.
40adb8ac-65ba-4b9c-82da-fd51ee2f7964
Knee, C.S.
d241249a-3d10-4b3e-9931-e3dd1029bb30
Weller, M.T.
36a60b56-049f-466c-a1d7-39d6b0d85ff4
Reading, J., Knee, C.S. and Weller, M.T.
(2002)
Syntheses, structures and properties of some osmates(IV,V) adopting the pyrochlore and weberite structures.
Journal of Materials Chemistry, 12 (8), .
(doi:10.1039/b201410f).
Abstract
Samples of the complex osmates CaOs2O7, Tl2Os2O7 - (x) and Pb2Os2O7 - (x) have been obtained by direct reaction of the component oxides in sealed tubes. The structures and compositions of these materials have been investigated by powder neutron and X-ray diffraction at room temperature and through variable temperature studies. Ca2Os2O7 adopts a stoichiometric, orthorhombic weberite structure but the distortion of the OsO6 octahedra and eightfold Ca-O co-ordinations decrease with increasing temperature indicating that this material lies close to the weberite/pyroch lore phase boundary. The lead and thallium phases adopt oxygen deficient, cubic pyrochlore structures under the synthesis conditions employed though no evidence was found of cation non-stoichiometry. Preliminary measurements of the electronic properties of weberite Ca2Os2O7 are also reported and discussed in comparison with the lead, thallium, cadmium and mercury osmate pyrochlores.
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Published date: 2002
Keywords:
high-pressure synthesis, neutron-diffraction, metal, transition, cd2os2o7, oxide
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Local EPrints ID: 19841
URI: http://eprints.soton.ac.uk/id/eprint/19841
PURE UUID: 89d55d4a-cfc2-49cf-a2fb-84a89680374c
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Date deposited: 22 Feb 2006
Last modified: 15 Mar 2024 06:19
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Author:
J. Reading
Author:
C.S. Knee
Author:
M.T. Weller
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