The Near-Infrared Combination Band Frequencies of Dioctahedral Smectites, Micas, and Illites

James L. Post
1993 Clays and clay minerals  
The highest frequency near-infrared (NIR) combination bands for specimens of four species of mica--montmorillonite-beidellite, illite, chlorite, and kaolinite--were correlated with respect to AI203 content. A direct linear correlation was found between the combination band positions and the AI203 contents of the montmorillonite-beidellite series, which may be given as: ~ cm -~ = (5.38 + 0.04) (% A1203) + (4412.8 --+ 0.9). A similar linear correlation for muscovite is: ~ cm ~ = (6.10 + 0.25) (%
more » ... 1203) Possible NIR band interferences are shown for different mineral mixtures, along with the correlation of different illites with muscovite. No combination bands were found in the frequency region 4425 cm l to 4625 cm ~ for specimens in which the A1203 content was only in the tetrahedral layer sites.
doi:10.1346/ccmn.1993.0410601 fatcat:zhjie5mqn5fmpmvjfljbj4677y