Study of structural defects in γ-MnO2 by Raman spectroscopy

The structural arrangement of γ-MnO2 is currently explained by a random intergrowth of pyrolusite layers in a ramsdellite matrix. The structures of a large variety of γ-MnO2 samples with various structural parameters Pr were studied by x-ray powder diffraction and Raman scattering spectroscopy. We show that elucidation of the quantitative determination of the structural disorder present in γ-MnO2 is accurate by Raman scattering spectroscopy. The Raman data for manganese dioxides with the γ-type structure are treated by a local environment model, which allows one to consider the relationship between the band wavenumber and the pyrolusite intergrowth that corresponds to the structural De Wolff defects. Copyright © 2002 John Wiley & Sons, Ltd.