Interpretation of Solid State 13C and 29Si Nuclear Magnetic Resonance Spectra of Kaolinite Intercalates

John G. Thompson
Geology Department, James Cook University of North Queensland Townsville, Queensland 4811, Australia

Abstract: 13C and 29Si nuclear magnetic resonance spectroscopy with magic-angle spinning bas been used to study the short-range ordering and bonding in the structures of intercalates of kaolinite with formamide, hydrazine, dimethyl sulfoxide (DMSO), and pyridine-N-oxide (PNO). The 29Si chemical shift indicated decreasing levels of bonding interaction between the silicate layer and the intercalate in the order: kaolinite: formamide (δ = −91.9, ppm relative to tetramethylsilane), kaolinite: hydrazine (−92.0), kaolinite: DMSO (−93.1). The 29Si signal of the kaolinite: PNO intercalate (−92.1) was unexpectedly deshielded, possibly due to the aromatic nature of PNO. The degree of three-dimensional ordering of the structures was inferred from the 29Si signal width, with the kaolinite: DMSO intercalate displaying the greatest ordering and kaolinite:hydrazine the least. 13C resonances of intercalating organic molecules were shifted downfield by as much as 3 ppm in response to increased hydrogen bonding after intercalation, and in the kaolinite: DMSO intercalate the two methyl-carbon chemical environments were non-equivalent (δ = 43.7 and 42.5).

Key Words: Dimethylsulfoxide • Formamide • Hydrazine • Intercalate • Nuclear magnetic resonance • Ordering • Pyridine-N-oxide

Clays and Clay Minerals; June 1985 v. 33; no. 3; p. 173-180; DOI: 10.1346/CCMN.1985.0330302
© 1985, The Clay Minerals Society
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