Structures of 6H perovskites Ba3CaSb2O9 and Ba3SrSb2O9 determined by synchrotron x-ray diffraction, neutron powder diffraction and ab initio calculations

Simple item page
dc.contributor.authorRowda, Ben_AU
dc.contributor.authorAvdeev, Men_AU
dc.contributor.authorLee, PLen_AU
dc.contributor.authorHenry, PFen_AU
dc.contributor.authorLing, CDen_AU
dc.date.accessioned2008-04-21T01:12:47Zen_AU
dc.date.accessioned2010-04-30T05:03:37Zen_AU
dc.date.available2008-04-21T01:12:47Zen_AU
dc.date.available2010-04-30T05:03:37Zen_AU
dc.date.issued2008-04en_AU
dc.date.statistics2008-04en_AU
dc.description.abstractThe structures of the 6H perovskites Ba3 B 2+Sb5+ 2O9, B = Ca and Sr, have been solved and refined using synchrotron X-ray and neutron powder diffraction data. Ba3CaSb2O9 and Ba3SrSb2O9 have monoclinic C2/c and triclinic space-group symmetries, respectively, while Ba3MgSb2O9 has ideal hexagonal P63/mmc space-group symmetry. The symmetry-lowering distortions are a consequence of internal chemical pressure' owing to the increasing effective ionic radius of the alkaline-earth cation in the perovskite B site from Mg2+ (0.72 Å) to Ca2+ (1.00 Å) to Sr2+ (1.18 Å). Increasing the effective ionic radius further to Ba2+ (1.35 Å) leads to decomposition at room temperature. The driving force behind the transition from P63/mmc to C2/c is the need to alleviate underbonding of Ba2+ cations in the perovskite A site via octahedral rotations, while the transition from C2/c to is driven by the need to regularize the shape of the Sb2O9 face-sharing octahedral dimers. Ab initio geometry-optimization calculations were used to find a triclinic starting model for Ba3SrSb2O9. © 2008, International Union of Crystallographyen_AU
dc.identifier.citationRowda, B., Avdeev, M., Lee, P. L., Henry, P. F., & Ling, C. D. (2008). Structures of 6H perovskites Ba3CaSb2O9 and Ba3SrSb2O9 determined by synchrotron x-ray diffraction, neutron powder diffraction and ab initio calculations. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 64(2), 154-159. doi:10.1107/S0108768108005041en_AU
dc.identifier.govdoc1235en_AU
dc.identifier.issn0108-7681en_AU
dc.identifier.issue2en_AU
dc.identifier.journaltitleActa Crystallographica Section B: Structural Science, Crystal Engineering and Materialsen_AU
dc.identifier.pagination154-159en_AU
dc.identifier.urihttp://dx.doi.org/10.1107/S0108768108005041en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/1087en_AU
dc.identifier.volume64en_AU
dc.language.isoenen_AU
dc.publisherInternational Union of Crystallographyen_AU
dc.subjectPerovskitesen_AU
dc.subjectSynchrotronsen_AU
dc.subjectNeutron diffractionen_AU
dc.subjectSymmetryen_AU
dc.subjectIonic compositionen_AU
dc.subjectDecompositionen_AU
dc.titleStructures of 6H perovskites Ba3CaSb2O9 and Ba3SrSb2O9 determined by synchrotron x-ray diffraction, neutron powder diffraction and ab initio calculationsen_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.8 KB
Format:
Plain Text
Description:
Download
Collections
Journal Articles