Static positional disorder in ulvöspinel: a single-crystal neutron diffraction study

Simple item page
dc.contributor.authorGatta, GDen_AU
dc.contributor.authorBosi, Fen_AU
dc.contributor.authorMcIntyre, GJen_AU
dc.contributor.authorHålenius, Uen_AU
dc.date.accessioned2016-08-14T23:52:03Zen_AU
dc.date.available2016-08-14T23:52:03Zen_AU
dc.date.issued2014-02-12en_AU
dc.date.statistics2016-08-15en_AU
dc.description.abstractA single-crystal neutron diffraction study of a synthetic ulvöspinel sample of composition Fe3+0.40Fe2+1.80Ti0.80O4 was performed to investigate the static positional disorder at the octahedrally coordinated M site. Anisotropic structural refinement was performed in the space group Fd3̄m against neutron Laue diffraction data collected at 298 K from two millimetric-sized crystals. Initial structure refinements were conducted with Fe and Ti sharing the M site (at 1/2, 1/2, 1/2), and their partial site occupancy was refined. The tetrahedrally coordinated T site (at 1/8, 1/8, 1/8) was modeled as fully occupied by Fe. For both crystals, the final R1 index was about 3% for 9 refined parameters and 129 unitetrahedrallyque reflections, with no significant residuals. As the atomic displacement factors obtained were anomalously high, according to the previous experimental findings, Fobs- and (Fobs–Fcal)-difference Fourier maps of the nuclear density were generated. Fourier maps showed a significant minimum located out-of-center of the M site, and indicating a displacement of the Ti4+ from the center of the octahedron. A further test refinement was successfully conducted with two mutually exclusive sites: MTi out-of-center (at 0.49, 0.49, 0.49) and MFe on the center (at 1/2, 1/2, 1/2). The resulting displacement of Ti from the octahedral center appears to be shorter than 0.15 Å. Using bond-valence theory, the out-of-center distortion of MTi4+ is interpreted as a result of intrinsic distortions in the ulvöspinel structure. The potential implication of the octahedral distortion on the behavior of ulvöspinel at non-ambient conditions is discussed.© 2014, Mineralogical Society of America.en_AU
dc.identifier.citationGatta, G. D., Bosi, F., McIntyre, G. J., & Hålenius, U. (2014). Static positional disorder in ulvöspinel: a single-crystal neutron diffraction study. American Mineralogist, 99(2-3), 255-260. doi:10.2138/am.2014.4702en_AU
dc.identifier.govdoc6941en_AU
dc.identifier.issn0003-004Xen_AU
dc.identifier.issue2-3en_AU
dc.identifier.journaltitleAmerican Mineralogisten_AU
dc.identifier.pagination255-260en_AU
dc.identifier.urihttp://dx.doi.org/10.2138/am.2014.4702en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/7299en_AU
dc.identifier.volume99en_AU
dc.language.isoenen_AU
dc.publisherGeoScience Worlden_AU
dc.subjectNeutron diffractionen_AU
dc.subjectAtomic displacementsen_AU
dc.subjectStructure functionsen_AU
dc.subjectAmbient temperatureen_AU
dc.subjectCrystalsen_AU
dc.subjectAtomsen_AU
dc.titleStatic positional disorder in ulvöspinel: a single-crystal neutron diffraction studyen_AU
dc.typeJournal Articleen_AU
Files
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles