Organically modified alpha-layered zirconium phosphate samples (ZrP(C-12)(x)) containing dodecyl groups bonded to the alpha-layers through P-O-C bonds have been prepared by reaction of 1,2-epoxydodecane solutions in tetrahydrofuran (THF) with gels of partially exfoliated zirconium phosphate in THF. Two dimensional correlation solid state NMR experiments for H-1-C-13 and H-1-P-31 nuclei have been used to prove the formation of P-O-C bonds arising from nucleophilic attack of POH mainly to carbon 1 and, to a lesser extent, to carbon 2 of epoxydodecane. ZrP(C-12)(x) samples with x in the range from similar to 0.5 to similar to 2.0 are thermally stable up to at least 200 degrees C, and their interlayer distance increases continuously with x from similar to 20 to similar to 35 angstrom. On the basis of structural considerations, it has been suggested that samples with low x values could intercalate aliphatic polymers. Accordingly, preliminary results have shown that molten polyethylene is intercalated in ZrP(C-12)(0.49) and ZrP(C-12)(0.73). These materials can therefore be regarded as filler candidates for polymer matrixes.