The structure and conductivity of a number of doped beta-PbF2 and BiF3 compounds have been investigated using neutron diffraction and impedance spectroscopy. Anion-deficient compounds in the system PbF2-MF with M = K, Rb display a high-temperature superionic phase with a body-centred cubic sublattice while an ordered cubic perovskite structure is observed for the composition PbCsF3. In the system PbF2-SnF2, the high-temperature structure of gamma-PbSnF4 with cubic symmetry has been characterised. The solid solutions in the system PbF2-BiF3, where vacancy clustering is observed, and in the systems BiF3-KF and BiF3-RbF have also been investigated at high temperature.