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Persistent URL http://purl.org/net/epubs/work/65389
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Record Id 65389
Title A (3+3)-Dimensional "Hypercubic" Oxide-Ionic Conductor: Type II Bi2O3-Nb2O5
Contributors
Abstract The high-temperature cubic form of bismuth oxide, ?-Bi2O3, is the best intermediate-temperature oxide-ionic conductor known. The most elegant way of stabilizing ?-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 ?-Bi2O3-like channels, explaining the high oxide-ionic conductivity compared to commensurately modulated phases in the same pseudobinary system.
Organisation ISIS , ISIS-SXD , ISIS-ILL , STFC
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Language English (EN)
Type Details URI(s) Local file(s) Year
Journal Article J Am Chem Soc 135, no. 17 (2013): 6477-6484. doi:10.1021/ja3109328 2013
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