Publication
Natural nanomaterials : reappraising the elusive structure of the nano-sized mineral ferrihydrite through X-Ray absorption spectroscopy at the iron K-edge
| dc.contributor.author | Figueiredo, M. Ondina | |
| dc.contributor.author | Silva, Teresa | |
| dc.contributor.author | Veiga, JP | |
| dc.date.accessioned | 2014-01-07T17:15:18Z | |
| dc.date.available | 2014-01-07T17:15:18Z | |
| dc.date.issued | 2013 | |
| dc.description.abstract | Ferrihydrite is natural ferric oxyhydroxide occurring exclusively nanocrystalline. With ideal formula 5 Fe2 O3 . 9 H2 O, ferrihydrite is quite abundant in sediments, weathering crusts and mine wastes, being characteristic of red pre-soils formed by loose weathered rock plus mineral debris (regoliths) and commonly designated as “2-line” or “6-line” on the basis of the broadened maxima observed in the X-ray diffraction pattern. Synthetic nanocrystalline “6-line” ferrihydrite was recently studied through methods based on atomic-pair distribution functions disclosing the possible occurrence of icosahedral clusters formed by twelve octahedra centred by an inner tetrahedron, all filled by Fe 3+ ions. However, Mössbauer studies were inconclusive about the existence of 4-coordinated iron, thus suggesting that the tetrahedral cation may well be Si4+. In view of such structural uncertainty, a XANES study at the Fe K-edge was undertaken on ferrihydrite from a regolith to ascertain the occurrence of tetrahedral iron. Comparison with data collected from well crystallized iron oxide and hydroxide minerals where Fe 3+/2+ ions occur in octahedral and tetrahedral coordination is described and the results so far obtained are discussed, showing that supplementary study is needed on the elusive structure of ferrihydrite. | por |
| dc.identifier.citation | Figueiredo, M. O.; Silva, T. P.; Veiga, J. P. - Natural nanomaterials : reappraising the elusive structure of the nano-sized mineral ferrihydrite through X-Ray absorption spectroscopy at the iron K-edge. In: Materials Science Forum, vols. 730-732, (2013), p. 931-935 | por |
| dc.identifier.uri | http://hdl.handle.net/10400.9/2103 | |
| dc.language.iso | eng | por |
| dc.relation.publisherversion | http://dx.doi.org/10.4028/www.scientific.net/MSF.730-732.931 | por |
| dc.subject | Nanominerais | por |
| dc.subject | Ferrohidrite | por |
| dc.subject | XANES | por |
| dc.subject | K-edge | por |
| dc.title | Natural nanomaterials : reappraising the elusive structure of the nano-sized mineral ferrihydrite through X-Ray absorption spectroscopy at the iron K-edge | por |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| oaire.citation.conferencePlace | Switzerland | por |
| oaire.citation.title | Materials Science Forum | por |
| person.familyName | Silva | |
| person.familyName | Veiga | |
| person.givenName | Teresa | |
| person.givenName | João Pedro | |
| person.identifier.ciencia-id | B916-C501-8AA3 | |
| person.identifier.ciencia-id | D81C-9EE7-8B61 | |
| person.identifier.orcid | 0000-0002-0306-1015 | |
| person.identifier.orcid | 0000-0001-5324-1586 | |
| person.identifier.rid | L-9359-2013 | |
| person.identifier.rid | J-3681-2013 | |
| person.identifier.scopus-author-id | 7005146574 | |
| rcaap.rights | openAccess | por |
| rcaap.type | article | por |
| relation.isAuthorOfPublication | e3d4c3a2-65c9-44d1-acd7-5c09468b7a24 | |
| relation.isAuthorOfPublication | 394657c1-49c9-4c04-9f55-28bd2ec8a62b | |
| relation.isAuthorOfPublication.latestForDiscovery | e3d4c3a2-65c9-44d1-acd7-5c09468b7a24 |