Small angle X-ray scattering under synchrotron radiation is a new method which allows on to calculate for each clay sample, the statistical distribution of the thickness of the layers and the average number of the individual layer which forms a particle. Hectorite, montmorillonite from Wyoming, montmorillonite from Camp Berteaux, nontronite and vermiculite have been studied by this technique. The following results were obtained :
- Parameters influencing the number of the individual layer and the swelling are the layer charges independently on the nature of the exchangeable cations.
- Swelling tends to be low in clay with tetrahedrally charged.
- Interparticle water is three or four times higher than in interlayer water.