Local ordering structure of meta-kaolinite and meta-dickite by the X-ray radial distribution function analysis

X-ray diffraction measurements on the structure of meta-kaolinite and meta-dickite have been carried out to obtain the radial distribution function (RDF). The distances and corresponding coordination numbers for Si-O and Al-O pairs were estimated by applying the pair function method. The SiO₄ tetrahedron remains unchanged in the dehydrated samples presently investigated, and the oxygen coordination number around aluminium was also found to be four. This implies the overall preference of AlO₄ tetrahedron at the expense of the parent AlO₂ (OH)₄ octahedron.