The effect the modification (pillarization) of montmorillonite clays from different locations has on the crystallographic lattice parameters of montmorillonite is determined. It is revealed through ultrahigh resolution transmission electron microscopy and analyzing microdiffraction patterns that pillarization raises the distance between montmorillonite structural units to 2.2 nm, while the intracrystal distance between the atoms grows by 0.4 n
