Protective Oxidation of a Layer Structured Manganese Titanate, RbXMnXTi2-XO4 (x = 0.75), in Acidic Solutions

A Iayer structured manganese titanate RbXMnXTi2-XO4 (x = 0.75) of the lepidoclocite type structure was oxidized with Ce4+ in sulfuric acid solutions. Although the titanate layer was dissolved into the acidic solutions without the oxidant, the layer showed high resistivity against the dissolution with the presence of Ce4+ ions, even in the same acidic conditions. A portion of the Rb ions were deintercalated corresponding to the amount of Mn3+ oxidized to Mn4+ in the manganese titanate layers.