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Title: | A (3+3)-Dimensional \"Hypercubic\" Oxide-Ionic Conductor: Type II Bi2O3-Nb2O5 |
Author: | Ling, Chris D. Schmid, Siegbert Blanchard, Peter E. R. Petricek, Vaclav McIntyre, Garry J. Sharma, Neeraj Maljuk, Andrey Yaremchenko, Aleksey A. Kharton, Vladislav V. Gutmann, Matthias Withers, Ray L. |
Keywords: | 3-DIMENSIONAL INCOMMENSURATE MODULATION NEUTRON POWDER DIFFRACTION SOLID-SOLUTION FUEL-CELLS STRUCTURAL-PROPERTIES BISMUTH SESQUIOXIDE SUPERSPACE GROUPS NODAL SURFACES SYSTEM PHASE |
Issue Date: | 2013 |
Publisher: | AMER CHEMICAL SOC |
Abstract: | The high-temperature cubic form of bismuth oxide, delta-Bi2O3, is the best intermediate-temperature oxide-ionic conductor known. The most elegant way of stabilizing delta-Bi2O3 to room temperature, while preserving a large part of its conductivity, is by doping with higher valent transition metals to create wide solid-solutions fields with exceedingly rare and complex (3 + 3)-dimensional incommensurately modulated \"hypercubic\" structures. These materials remain poorly understood because no such structure has ever been quantitatively solved and refined, due to both the complexity of the problem and a lack of adequate experimental data. We have addressed this by growing a large (centimeter scale) crystal using a novel refluxing floating-zone method, collecting high-quality single-crystal neutron diffraction data, and treating its structure together with X-ray diffraction data within the superspace symmetry formalism. The structure can be understood as an \"inflated\" pyrochlore, in which corner-connected NbO6 octahedral chains move smoothly apart to accommodate the solid solution. While some oxide vacancies are ordered into these chains, the rest are distributed throughout a continuous three-dimensional network of wide delta-Bi2O3-like channels, explaining the high oxide-ionic conductivity compared to commensurately modulated phases in the same pseudobinary system. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19568 |
DOI: | 10.1021/ja3109328 |
ISSN: | 0002-7863 |
Publisher Version: | 10.1021/ja3109328 |
Appears in Collections: | CICECO - Artigos |
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File | Description | Size | Format | |
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A (3+3)-Dimensional Hypercubic Oxide-Ionic Conductor Type II Bi2O3-Nb2O5_10.1021ja3109328.pdf | 463.89 kB | Adobe PDF |
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