SnK, PbL3, and BaL3 EXAFS, X-ray diffraction and 119Sn Mössbauer spectroscopic studies of ordered MSnF4 (M = Pb and Ba) fluoride ionic conductors with the α-PbSnF4 structure

The high performance fluoride ion conductors α-PbSnF4 and BaSnF4 have been studied using X-ray diffraction, 119Sn Mössbauer spectroscopy, and EXAFS. X-ray diffraction shows the unit-cell is a tetragonally distorted fluorite-type, with ordering of the metals which results in a superstructure along the c axis. The SnK, PbL3, and BaL3 X-ray absorption spectra of α-PbSnF4 and BaSnF4 as well as model compounds (SnO, β-PbF2, and BaF2) have been …