Institutional Repository
Technical University of Crete
EN  |  EL



My Space

A simple approach to the identification of trioctahedral smectites by X-ray diffraction

Christidis Georgios, Eleni Koutsopoulou

Full record

Year 2013
Type of Item Peer-Reviewed Journal Publication
Bibliographic Citation G. Christidis, E. Koutsopoulou, " A simple approach to the identification of trioctahedral smectites by X-ray diffraction " ,C. Min., vo.48 ,no.5 ,pp. 687-696 ,2013.doi:10.1180/claymin.2013.048.5.22
Appears in Collections


A new method for identifying the trioctahedral smectites saponite, stevensite and hectorite is proposed in this study. The method is based on differences in the X-ray diffraction (XRD) patterns of the three smectites after (a) heating at 500°C for 90 min and (b) glycerol solvation of the Cs-forms of the smectites for 20 h. After heating at 500°C, well below the dehydroxylation temperature of the three smectites, saponite and hectorite re-expand upon ethylene glycol (EG) solvation, whereas stevensite layers remain collapsed. Saponite forms one-layer and hectorite two-layer complexes after Cs-saturation and glycerol solvation. Cs-stevensite displays a gradual increase in d 001 with increasing solvation time in glycerol vapours and forms two-layer glycerol complexes with prolonged solvation. Except for the individual Mg-smectites, the proposed method may be used to identify compositional heterogeneity that may exist in the smectites. Furthermore, it should be useful in identifying the individual trioctahedral Mg-smectites when present in mixtures, and in detecting interstratified layers of different Mg-trioctahedral smectites. Application of the method revealed that the SYnL-1 laponite (CMS Source Clay Project) is not homogeneous but consists of hectorite, stevensite and possibly mixed-layer hectorite/stevensite layers.