Please use this identifier to cite or link to this item: http://www.repositorio.ufop.br/handle/123456789/11185
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dc.contributor.authorAlboom, Antoine Van-
dc.contributor.authorCosta, Geraldo Magela da-
dc.contributor.authorGrave, Eddy De-
dc.date.accessioned2019-05-03T15:25:20Z-
dc.date.available2019-05-03T15:25:20Z-
dc.date.issued2018-
dc.identifier.citationALBOOM, A. V.; COSTA, G. M. da; GRAVE, E. D. Defciency of water molecules in the crystallographic structure of vauxite. Physics and Chemistry of Minerals, v. 45, n. 3, p. 249–257, mar. 2018. Disponível em: <https://link.springer.com/article/10.1007/s00269-017-0913-2> Acesso em: 15 set. 2017pt_BR
dc.identifier.issn1432-2021-
dc.identifier.urihttp://www.repositorio.ufop.br/handle/123456789/11185-
dc.description.abstractA vauxite mineral sample from Huanuni, Bolivia, was studied by XRD, TGA and Mössbauer spectroscopy. The XRD revealed the sample as having the typical triclinic structure of vauxite. The chemical formula was determined as (Fe0.88Mn0.01)Al1.99(PO4)2(OH)1.75(H2O)5.31, implying some Fe2+, OH− and H2O deficiencies. The TGA curve showed ca. 27% loss of weight over a temperature range from 80 to 400 °C, supposedly due to the loss of water and hydroxyl groups. For the first time, Mössbauer spectra for vauxite were collected over a wide temperature range between 9 and 310 K. No magnetic ordering was detected. The spectra could be successfully and consistently analyzed by a superposition of four doublet subspectra. On the basis of the relation between the center shift and the mean Fe-ligand distance on the one hand and the center shift values for the various doublets on the other hand, one doublet was assigned to Fe(2). For the other doublets, it is proposed that, as a result of the H2O deficiency in the structure of the present vauxite sample, vacancies are present in the second coordination spheres of some Fe(1) and that these vacancies affect the quadrupole splitting of the corresponding Fe(1) cations, thus causing three Fe(1) doublet components in the Mössbauer spectra. The temperature variations of center shift and quadrupole splitting of the various doublet contributions are presented and discussed.pt_BR
dc.language.isoen_USpt_BR
dc.rightsrestritopt_BR
dc.subjectMössbauer spectroscopypt_BR
dc.subjectQuadrupole splittingpt_BR
dc.subjectCenter shiftpt_BR
dc.subjectCrystal field calculationpt_BR
dc.titleDefciency of water molecules in the crystallographic structure of vauxite.pt_BR
dc.typeArtigo publicado em periodicopt_BR
dc.identifier.uri2https://link.springer.com/article/10.1007/s00269-017-0913-2pt_BR
dc.identifier.doihttps://doi.org/10.1007/s00269-017-0913-2pt_BR
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