A comprehensive characterization of dioctahedral smectites

The term 'montmorillonite' encompasses a wide range of chemical compositions and structures. Comprehensive and reliable characterization is essential for unambiguous classification. Twenty eight purified, Na-exchanged smectites ( 0.3mol/f.u. are trans-vacant, mostly with additional cis-vacancies. Tetrahedral substitution also appeared to be a function of the number of trans-vacancies. The parameters analyzed provide the basis for a new descriptive classification system