Abstract
The soft chemical approach to synthesis and control of the properties for functional inorganic materials by using ionexchange reactions of layered manganese oxides and layered titanates were reviewed. The metal ion templates can be intercalated into the layered manganese oxides by ion-exchange reactions. The layered structure of the manganese oxide transforms to tunnel structure under hydrothermal conditions, and the tunnel size is dependent on the size of the template ions in the interlayer space. Eight types of tunnel manganese oxides have been obtained by using this method. The tunnel manganese oxides show excellent ion-sieve properties. The sandwich layered compounds can be prepared by polymerizing ions in the interlayer space, and also by exfoliation-restacking reaction of the layered compound. The BaTiO3 and TiO2 with the desired morphology can be synthesized by topotactic structural transformations from the layered titanates. Furthermore, BaTiO3 and TiO2 thin films with crystal-axis preferred orientation can be prepared on the polycrystalline substrates by utilizing the exfoliation-restacking reaction and the topotactic structural transformation reaction.
