Structures and solid solution mechanisms of pyrochlore phases in the systems Bi2O3-ZnO-(Nb, Ta)2O5

• Main Authors: Tan, Kar Ban, Khaw, Chwin Chieh, Lee, Chnoong Kheng, Zainal, Zulkarnain, Miles, Gabrielle
• Format: Article
• Language: English; English
• Published: Elsevier 2010
• Online Access: http://psasir.upm.edu.my/id/eprint/16873/1/Structures%20and%20solid%20solution%20mechanisms%20of%20pyrochlore%20phases%20in%20the%20systems%20Bi2O3.pdf; http://psasir.upm.edu.my/id/eprint/16873/
• Institution: Universiti Putra Malaysia

The crystal structures of two pyrochlore phases have been determined by Rietveld refinement of combined X-ray and neutron powder diffraction data. These are stoichiometric, Bi1.5 ZnTa1.5O7 and non-stoichiometric Bi1.56Zn0.92Nb1.44O6.86. In both structures, Zn is distributed over A- and B-sites; Bi and Zn are displaced off-centre, to different 96g A-site positions; of the three sets of oxygen positions, O(1) are full, O(2) contain vacancies and O(3) contain a small number of oxygen, again in both cases. Comparisons between these structures, those of related Sb analogues and literature reports are made.