The influence of structural Fe, Al and Mg on the infrared OH bands in spectra of dioctahedral smectites
- 1 December 2002
- journal article
- Published by Mineralogical Society in Clay Minerals
- Vol. 37 (4), 607-616
- https://doi.org/10.1180/0009855023740063
Abstract
Visible to near-infrared (NIR) reflectance spectra and mid-IR transmittance spectra are presented here for a collection of dioctahedral smectites. Analysis of the structural OH vibrations is performed by comparing the NIR combination and overtone bands with fundamental stretching and bending absorption features in the mid-IR region. Second derivatives are used to determine the actual band centres, which are often shifted slightly by a spectral continuum in the reflectance or transmittance spectra. New bands have been identified near 4170 and 4000 cm–1 in the NIR spectra of nontronite with tetrahedral substitution. A related band is observed near 4100 cm–1 for montmorillonites with substantial tetrahedral and/or octahedral substitution. These bands are correlated with the mid-IR bands near 680 cm–1 for nontronite and near 630 cm–1 for montmorillonite. Comparison of the OH overtone and combination bands with the fundamental stretching and bending vibrations gives consistent results.Keywords
This publication has 20 references indexed in Scilit:
- The influence of octahedral and tetrahedral cation substitution on the structure of smectites and serpentines as observed through infrared spectroscopyClay Minerals, 2002
- Mineralogical and chemical characteristics of five nontronites and Fe-rich smectitesClay Minerals, 1999
- Refined Relationships between Chemical Composition of Dioctahedral Fine-Grained Micaceous Minerals and Their Infrared Spectra Within the OH Stretching Region. Part II: The Main Factors Affecting OH Vibrations and Quantitative AnalysisClays and Clay Minerals, 1997
- Refined Relationships between Chemical Composition of Dioctahedral Fine-Grained Mica Minerals and Their Infrared Spectra within the OH Stretching Region. Part I: Identification of the OH Stretching BandsClays and Clay Minerals, 1997
- Characterisation of moderately acid-treated, size-fractionated montmorillonites using IR and MAS NMR spectroscopy and thermal analysisJournal of Materials Chemistry, 1995
- Infrared Spectroscopic Analyses on the Nature of Water in MontmorilloniteClays and Clay Minerals, 1994
- Infrared study of octahedral site populations in smectitesClay Minerals, 1994
- Reflectance and Mössbauer spectroscopy of ferrihydrite-montmorillonite assemblages as Mars soil analog materialsGeochimica et Cosmochimica Acta, 1993
- Water Molecules and Hydroxyl Groups in Montmorillonites as Studied by Near Infrared SpectroscopyClays and Clay Minerals, 1981
- A MÖssbauer and I.R. Spectroscopic Study of the Structure of NontroniteClays and Clay Minerals, 1976