The crystal structure of alpha-PbSnF4 and its anion diffusion mechanism

The crystal structure of PbSnF4 and its anion diffusion mechanism were investigated by impedance spectroscopy, powder neutron diffraction and computer simulation methods. The ionic conductivity of PbSnF4 underwent small and abrupt increases at 60 K and 672 K characteristic of the α → β and β → γ phase transitions. The computer simulations, using interionic potentials derived from first-principles calculations and containing realistic representations of polarization effects were observed to be in good agreement with the ionic conductivity. The high ionic conductivity of α-PbSnF4 involved only a fraction of the anions and was restricted to two-dimensional planes