Intercalation of a crown ether (1 8-crown-6) into layered silicates was investigated. Intercalation compounds with the basal spacings of ca. 1.9 nm were obtained by the solid-state reactions between K-, Rb-, and NH 4 -montmorillonites and 18-crown-6, while the basal spacings of the products were different (1.4, 1.5, and 1.5 nm for K-, Rb-, and NH 4 -montmorillonites, respectively) when a methanolic solution of 18-crown-6 was employed. 18-crown-6 was intercalated into the interlayer space of non swelling K-fluor-tetrasilicic mica probably due to the strong interactions between interlayer cations and 18-crown-6. The reaction between K-kenyaite and 18-crown-6 gave an intercalation compound with the basal spacing of ca. 3.0 nm. It has been proved that the reactions between the layered silicates and 18-crown-6 without solvents are novel synthetic ways to lead intercalation compounds.