X-ray powder diffraction analysis was performed using a Rigaku Ultima IV X-ray diffractometer equipped with a Cu Kα radiation source (λ = 1.540 59 Å). Xray total scattering data were collected at the 11-ID-B beamline at the Advanced Photon Source, Argonne National Laboratory, using high energy X-rays (λ = 0.2128 Å) up to a high momentum transfer value, Q max = 18 Å-1 . The raw total scattering data were processed using Fit2D . Pair-distribution function (PDF) data, G(r), were derived by Fourier transformation after eliminating Kapton and background contributions using PDFgetX2 . Refinement of the PDF data was performed using PDFgui , setting the Q damp parameter at 0.04. The refined parameters included the lattice parameter, the scale factor, s ratio -the correction for the low-r to high-r PDF peak ratio due to correlated motion of bonded atoms -and isotropic atomic displacement factors. 19 F solid-state magic angle spinning (MAS) NMR experiments were performed on a Bruker Avance III spectrometer operating at 7.0 T ( 19 F Larmor frequency of 282.2 MHz), using a 1.3 mm CP-MAS probe head. Room temperature 19 F MAS spectra were recorded using a Hahn echo sequence with an interpulse delay equal to one rotor period. The 90 • pulse length was set to 1.55 µs and the recycle delay was set to 20 s. 19 F spectra were referenced to CFCl 3 and fitted using the DMFit software .