Abstract: The present paper reports the method that the monodispersed particles of cadmium sulfide are formed by precipitation in the nonionic microemulsion.The microemulsion consisting of Cd²⁺ ions was mixed with that consisting of S₂- ions at 25 ℃- Various sizes and shapes of monodispersed particles of CdShave been obtained by adjusting the constitution of the microemulsion consisting of Tx10-cyclohexane-octanol, ions concentration and different cadmium salts.Furthermore, the conditions affecting the particle size and shape, the relationship between the reactants and the precipitation regions are studied and the effects of ions on the mierocircumstance in the microemulsion are discussed.

Key words: Colloidal semiconductors, Cadmium sulfide, Monodispersed colloids, Nonionic microemul-sion