Abstract: A new type of organomontmorillonite (C₁₆-MMT) is reported. Camontmo rillonite (Ca-MMT) was directly modified with hexadecyl trimethyl ammonium bromide viaionexchange. The effects of dispose measure of montmorillonite and ionexchange conditions including ionexchange time and ionexchange times on the structure of C₁₆-MMT were investigated by X-ray diffraction (XRD). The X-ray patterns reveal that the interlamellar spacing of the clay, corresponding to the (001) plane peak, increases from 1.49　nmof the purifiedCa-MMT to 2.21　nm of C₁₆-MMT.

Key words: Ca-montmorillonite, ion-exchanged method, interlamellar spacing