Study of structural defects in γ-MnO2 by Raman spectroscopy

The structural arrangement of gamma-MnO2 is currently explained by a random intergrowth of pyrolusite layers in a ramsdellite matrix. The structures of a large variety of gamma-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 gamma-MnO2 is accurate by Raman scattering spectroscopy. The Raman data for manganese dioxides with the gamma-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 (C) 2002 John Wiley Sons, Ltd.