Structures and dynamics of n-dodecyltrimethylammonium ions intercalated into sodium octosilicate and tetrasilicicfluoromica were studied by powder x-ray diffraction, and ¹³C CP/MAS and ¹H NMR measurements. In the octosilicate, cations form a 2D-crystalline state in which long axes of intercalated alkylammonium ions were shown to be inclined to silicate layers and polymethylene chains (–CH₂–)_n take the all-trans conformation. On the other hand, in the tetrasilicicfluoromica, cations form disordered arrangements with random conformations of alkyl-chains, considered to be in a 2D-amorphous state. Based on the NMR results, the dynamic behaviour of these ions in 2D space is discussed.