Identification of randomly interstratified illite/smectite with basal peak widths

This study formulates the following relationship for identifying randomly interstratified illite/smectite using the integrated peak widths (β) for the first-order reflections after ethylene-glycolation (EG) and thermal dehydration (TD) treatments: \[\mathit{p_{i}}\ =\ {-}\frac{{\beta}_{EG}\ {-}\ 0.589{\beta}_{TD}}{1.324{\beta}_{TD}\ {-}\ 3.911}\] where p i is the proportion of interstratified illite layers. The relationship minimizes the effect of crystallite thickness on the evaluation of p i , which has been a critical source of error in the previous methods using peak position and intensity.