Structural investigations of natural and synthetic chlorite minerals by X-ray diffraction, Mossbauer spectroscopy and solid-state nuclear magnetic resonance
2006 (English)In: Clays and clay minerals, ISSN 0009-8604, ISSN 0009-8604, Vol. 54, no 2, 252-265 p.Article in journal (Refereed) Published
The structures of one synthetic and two natural chlorites of the chlinochlore type were explored using X-ray diffraction, magic-angle spinning nuclear magnetic resonance (NMR) and Mossbauer spectroscopy. Rietveld refinements indicated that all structures are of the trioctahedral ordered IIb polytype. Mossbauer spectra provided the ratio Fe-II/Fe-III but gave no evidence for the presence of Fe-III in the brucite-like sheet. We also report unit-cell parameters, Mossbauer isomeric shifts, Si-29 NMR chemical shifts as well as Al-27 isotropic shifts and quadrupolar coupling parameters. Very broad Si-29 NMR peaks from the natural samples prevented us from obtaining accurate information on the Si-Al ordering in the tetrahedral sheets; the limitations of Si-29 NMR as applied to natural chlorites are discussed. High-resolution 3QMAS NMR resolved the Al-27 signal of the M4 octahedral site in the brucite-like sheet from the other three Al signals of crystallographically inequivalent octahedral positions.
Place, publisher, year, edition, pages
2006. Vol. 54, no 2, 252-265 p.
Al-27 NMR, cation distributions, chlorite, layered mineral, mineral structure, Mossbauer spectroscopy, Si-29 NMR, XRD
IdentifiersURN: urn:nbn:se:kth:diva-24161DOI: 10.1346/CCMN.2006.0540210ISI: 000237465700010ScopusID: 2-s2.0-33646558014OAI: oai:DiVA.org:kth-24161DiVA: diva2:344376
QC 201008192010-08-192010-08-192014-04-07Bibliographically approved