Layered vanadyl organophosphonates VORPO(3) . xH(2)O were brought into contact with primary alkylamines CnH2n+1NH2 (n = 3-6). Intercalation compounds have been characterized by their basal spacings, thermogravimetric analysis (TGA), XANES, and IR spectra. Regardless of the starting vanadyl phosphonate, a plot of the interlayer distances of the intercalates vs the number of carbon atoms (n(c)) in the alkyl chain of the amine indicates that amine molecules were packed in the interlamellar space either as bilayer or as an interdigitated monolayer, depending on n(c). Hydrolysis of the phosphonate groups, oxidation of vanadium atoms, and the nature of the final products are described.