Inelastic Neutron Scattering and Transmission Electron Microscope Studies of Lead Dioxide

The complementary techniques of inelastic neutron scattering and high resolution transmission electron microscopy have been used to study different aspects of the constitution of several forms of lead dioxide. The neutron scattering techniques, which are particularly sensitive to the presence of hydrogenous species, indicate that lead dioxide can accommodate widely varying amounts of hydrogen. The vibration spectra, recorded after various dehydration procedures, do not show sharp characteristic vibrations consistent with hydroxyl groups similar to those known to be present in other hydrogen‐containing oxides. They suggest that the temperature‐induced changes observed are consistent with the presence of adsorbed water. There appears to be a relationship between the amount of hydrogen present in a sample of , as measured by neutron transmission, and the proportion of reduced lead present ( i.e. , other than Pb 4+ ) determined by chemical analysis. The electron microscopy has allowed the first direct imaging of the crystal structure of . This form of lead dioxide, like , is prone to coherent structure intergrowth but, unlike , the range of defects present does not include planar faults.