Variations in interlayer cation sites of clay minerals as studied by ¹³³Cs MAS nuclear magnetic resonance spectroscopy

This paper describes the results of a ¹³³Cs MAS NMR study of a number of Cs-exchanged clay minerals and the relationship of the ¹³³Cs chemical shift to chemical and structural parameters. In hectorite, Cs occupies a number of different sites depending on the structure, composition, and hydration state of the clay. Increased rotational distortions of the basal O sheet, total layer charge, and tetrahedral Al³⁺ substitution for Si⁴⁺ correlate with increased deshielding of the ¹³³Cs chemical shifts for both hydrated slurry and dehydrated samples. -from Authors