Structural evolution of nacrite as a function of the nature of intercalated organic molecules

Nacrite has been intercalated with two polar organic molecules: dimethyl su lfoxide (DMSO) and N-methylacetamide (NMA). The homogeneous nacrite complex es have been studied by X-ray diffraction (XRD) and infrared (IR) spectrosc opy. The XRD study is based on a comparison between experimental and calcul ated patterns. The structures of the intercalated compounds have been deter mined, including the mutual positions of the layers after intercalation and the positions of the intercalated molecules in the interlayer space. It ha s been shown that the intercalation process causes not only a swelling of t he interlayer space but also a shift in the mutual in-plane positions of th e layers. This shift depends on the nature of the intercalated molecules an d is related to their shape and the hydrogen bonds which are established wi th the surrounding surfaces. For a given molecule, the intercalation proces s is the same for the different polytypes of the kaolinite family. These XR D results are consistent with those of IR spectroscopy.