The behaviour of clays is not still well understood. Most information
concerning clays has been obtained by techniques which give statistical
information on the structure and chemistry. However papers have reported
results from scanning and high resolution electron microscopy. This work
presents a nanoscopic approach, using electron energy loss spectroscopy
(EELS), of different purified clays. EELS permitted to detect all the
elements found by classical chemistry at a macroscopic level. In particular
it made it possible to determine the Si/Al ratio in kaolinite (Si/Al ~ 1), smectite and illite (Si/Al ~ 2). In all the cases, the K edge
oxygen energy loss near edge structure (ELNES) is often similar to that of
other clays we studied, but a strong heterogeneity has been observed. It was
also possible to highlight an influence of the presence of iron on the
profile of the oxygen peak.