Abstract: The structure of NiSM M(Nickel-Substituted Mica Montmorillonite) samplesprepared under different conditions were characterized by means of XRD analysis,CEC andsurface area measurements,and IR analysis. It was shown that mote nickel enters the layerstructure of NiSM M when more nickel is added to starting matcrials for the synthesis. NIS-MM has the same layer structure as that in natural smectite.There are exchangable cationsbetween the layers, most of which are The d_(060) value of XRD pattern and the skeletalvibration of IR spectra reveal that nickel ions are located at the centers of octahedra inthe unit layer of NiSMM.