Activation volumes in the high-temperature region for silver chloride and silver bromide

Measurements of ionic conductivity as a function of pressure have been made for solid AgCl and AgBr in the high-temperature region where non-Arrhenius behavior has been reported at normal pressure. The results show that the activation volume increases considerably with increasing temperature and decreases with increasing pressure. The large increase in the activation volume as a function of temperature can be explained by the onset of a gradual transition to a solid-electrolyte phase such as those found in many materials with the fluorite structure.