Phase transition and ion dynamics in cubic PbSnF₄ (γ-PbSnF₄), which shows high conductivity ~10⁻⁴ S/cm at room temperature, is examined by using ¹⁹F/¹¹⁹Sn/²⁰⁷Pb solid-state NMR at 7 T and 14 T. By comparing with the corresponding NMR data of tetragonal PbSnF₄ (β-PbSnF₄) obtained by annealing the γ form at 200 °C, we show that, while local structures around both Sn and Pb atoms are similar in the two forms, ion dynamics are markedly different. In the γ form, many F-vacancies existing around Sn and Pb lead the defect-driven ion conduction less effective as the fluoride ions tend to move locally. Further, we show that the γ-to-β phase transition is preceded by slowing down of a part of mobile fluoride ions at temperature ca. 100 °C below the transition temperature observed by DSC.

在立方PbSnF相变和离子动力学₄（γ-PbSnF ₄），其显示了高导电性〜10 ^-4  S / cm的在室温下，通过使用检查¹⁹ F / ¹¹⁹的Sn / ²⁰⁷铅固体NMR在7Ť和14 T.通过与四方PbSnF的相应NMR数据进行比较₄（β-PbSnF ₄）通过在200°C下对γ形式进行退火获得，结果表明，尽管Sn和Pb原子周围的局部结构在两种形式中相似，但离子动力学却显着不同。在γ形式中，Sn和Pb周围存在许多F空位，导致缺陷驱动的离子传导效率降低，因为氟化物离子倾向于局部移动。此外，我们表明，在温度ca之前，从γ到β的相变先于一部分移动氟离子的放慢。比DSC观察到的转变温度低100°C。