Clays and Clay Minerals, Vol. 54, No. 2, 252-265, 2006.
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Authors
Zazzi, Asa
Hirsch, Tomas K.
Leonova, Ekaterina
Kaikkonen, Andrei
Grins, Jekabs
Annersten, Hans
Eden, Mattias
Issue Date
2006
Type
Article
Language
en_US
Keywords
Periodicals , Geology , 27Al NMR , Cation Distributions , Chlorite , Layered Mineral , Mineral Structure , MoE ssbauer Spectroscopy , 29Si NMR , XRD
Alternative Title
Structural Investigations Of Natural And Synthetic Chlorite Minerals By X-ray Diffraction, Moe Ssbauer Spectroscopy And Solid-state Nuclear Magnetic Resonance
Abstract
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 MoÈssbauer spectroscopy. Rietveld refinements indicated that all structures are of the trioctahedral ordered IIb polytype. MoÈ ssbauer spectra provided the ratio IIFe/IIIFe but gave no evidence for the presence of IIIFe in the brucite-like sheet. We also report unit-cell parameters, MoÈssbauer isomeric shifts, 29Si NMR chemical shifts as well as 27Al isotropic shifts and quadrupolar coupling parameters. Very broad 29Si NMR peaks from the natural samples prevented us from obtaining accurate information on the Si-Al ordering in the tetrahedral sheets; the limitations of 29Si NMR as applied to natural chlorites are discussed. High- resolution 3QMAS NMR resolved the 27Al signal of the M4 octahedral site in the brucite-like sheet from the other three Al signals of crystallographically inequivalent octahedral positions.
Description
gsccm-54-2-10-zaz.pdf 1.03MB PDF/A Document.
Citation
Clays and Clay Minerals, Vol. 54, No. 2, 252-265, 2006.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018, The Clay Minerals Society