The defect parameters in beta-PbF2 that have been determined to date from the association and extrinsic regions of the isobaric conductivity plot as well as from conductivity measurements under various pressures, are studied. We find that, in the low temperature range where bulk elastic and expansivity data are available, the defect volumes scale linearly with the defect enthalpies with a slope which is governed by bulk qualities. A deviation from linearity is observed in the high temperature range from which the relevant parameters for the anion Frenkel formation process are deduced. (c) 2008 Elsevier B.V. All rights reserved.