A mixed alkali metal titanate of composition A x Ti 2-x/3 Li x/3 O 4 (A ) K, Rb, Cs) has been prepared and its ion-exchange/intercalation properties have been explored. Solid-state calcination of appropriate mixtures of TiO 2 and alkali metal carbonates produced the titanate at a stoichiometry of x ) 0.80 for A ) K, 0.75 for Rb, and 0.70 for Cs. Rietveld refinement on neutron diffraction data confirmed that the orthorhombic structure is comprised of lepidocrocite-related host layers of Ti 2-x/3 Li x/3 O 4 and charge-balancing A ions in the interlayer domain. Complete extraction of both alkali metal ions was achieved by acid-leaching, producing a new protonic titanate of H 4x/3 Ti 2-x/3 O 4 ‚H 2 O. This phase is distinguished from isomorphous related compounds in terms of high proton content as a consequence of exchangeable Li ions located in the host framework. The material took up alkali metal ions and organoammonium ions from aqueous media. These ion-exchange and intercalation reactions brought about expansion/contraction of the gallery height and lateral displacement of the layers. The resulting various types of layer sequence can be understood in terms of the nature of the interlayer species.

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