The structures of β-Pb0.9Sn0.1F2 (Sn10) and β-Pb0.8Sn0.2F2 (Sn20) were determined by using single-crystal intensity data from 4-circle diffractometry. It was found that the structures had cubic symmetry, with a = 5.946Å, V = 210.2Å3, Fm3m for Sn10 and a = 5.957Å, V = 211.4Å3, Fm3m for Sn20. The structures were refined to wR = 4.2% for Sn10, and 3.6% for Sn20, by using the least-squares method and 76 unique reflections with |F0|>3σ(|F0|). The F ions were deduced to be statistically distributed over 32 sites with (0.25+δ, 0.25+ δ, 0.25+δ), where δ was the displacement from the normal F site and increased with SnF2 content. The isotropic temperature factor for Sn20 (16.5Å2) was large when compared with that for Sn10 (3.18Å2). The ionic conductivity of the system increased with increasing magnitude of the temperature factor for the fluoride ion.

Ionic Conduction and Crystal Structure of β-Pb1−xSnxF2 (x ≤ 0.3). Y.Ito, T.Mukoyama, K.Ashio, K.Yamamoto, Y.Suga, S.Yoshikado, C.Julien, T.Tanaka: Solid State Ionics, 1998, 106[3-4], 291-9