Pillaring studies on four layered oxides, (\mathrm{KCa}{2} \mathrm{Nb}{3} \mathrm{O}{10}, \mathrm{KCa}{3} \mathrm{Nb}{3}) (\mathrm{TiO}{13}, \mathrm{KCa}{4} \mathrm{Nb}{3} \mathrm{Ti}{2} \mathrm{O}{16}), and (\mathrm{KCa}{2} \mathrm{Sr}{0.5} \mathrm{Nb}{3} \mathrm{Ti}{0.5} \mathrm{O}{11.5}), possessing Ruddlesden-Popper related structures have been carried out. The aluminum keggin ion, (\left[\mathrm{Al}{13} \mathrm{O}{4}(\mathrm{OH}){24}\left(\mathrm{H}{2} \mathrm{O}\right){12}\right]^{7+}), was used as the polymeric cation for the pillar. These samples were characterized by (\mathrm{X})-ray diffraction, thermogravimetric analysis, infrared spectroscopy, neutron activation analysis, and sorption studies. X-ray diffraction and other structural studies suggest that the polymeric cations were incorporated into the interlayer and upon calcination the layer thicknesses observed correspond to that expected for the formation of the dehydrated polymers in between the layers as a composite. BET surface area measurements and sorption experiments indicate that these products arc nonporous oxides suggesting that the interlayer regions are stuffed rather than pillared. O 1994 Academic Press, Inc.