XRD profile analysis of intercalated clays in low angle region

Powder diffractograms of intercalated clays (especially those of smectite g roup) usually exhibit a large (001) peak broadening which may be accompanie d with a significant peak shift due to instrumental or physical factors. As a result, very different d-spacings are often presented in the literature and the d-spacings estimated from different orders of basal lines do not ma tch together, which is usually interpreted as a mixed structure. In this pa per the effects influencing the diffraction line shape and peak position at the low angle region are shown on three examples. The peak shift due to Lo rentz-polarization factor is calculated for lines differing in the halfwidt h, The peak shift caused by the angular dependence of structure factor magn itude is illustrated on the example of montmorillonite intercalated with Al -complexes. The third example illustrates, how the different angle dependen cies of structure factor affect the measured intensify or different water c ontent in the interlayer of Mg-montmorillonite.