Adsorption of Pyridine N-Oxide onto Montmorillonite

S. Olejnik*, A. M. Posner and J. P. Quirk
Department of Soil Science and Plant Nutrition, University of Western Australia, Nedlands, Western Australia 6009
* Present address: Department of Chemistry, University of Birmingham, Edgbaston, Birmingham, England.

Abstract: Pyridine N-oxide and montmorillonite form interlamellar complexes with basal spacings of 14·7 and 21 Å. The former corresponds to a monolayer with a tilted orientation of the pyridine ring; the latter comprises a double layer of molecules between the clay sheets. Infrared spectra show that pyridine N-oxide bonds through the NO group; in the 21 Å complexes it is coordinated to the exchangeable cations through water molecules acting as bridges which themselves are directly coordinated to the cations. In the 14·7 Å complexes a splitting of the ν(NO) band occurs with the more polarizing cations Mg and Ca; the two bands correspond to pyridine N-oxide molecules directly coordinated to the cation and to other molecules coordinated through bridging by water molecules. Cs montmorillonite forms complexes with a basal spacing of approximately 14·7 Å which also shows a splitting of the ν(NO) band.

Clays and Clay Minerals; June 1973 v. 21; no. 3; p. 191-198; DOI: 10.1346/CCMN.1973.0210308
© 1973, The Clay Minerals Society
Clay Minerals Society (www.clays.org)