The EIS spectra of t-BaSnF4 (inset) as well as XRD patterns of BaSnF4 after applying the milling procedure described in section 2.1 and after subsequent annealing are presented in Figure . After applying the ball milling procedure, the sample mainly consists of nanocrystalline cubic-BaSnF4, along with phase fractions closer to the starting materials SnF2 and BaF2 with certain amounts of defects possibly introduced on milling (indicated by small changes of lattice parameters) due to the mechanical impacts. The broadening and asymmetry (extended tails to higher diffraction angles) for the reflections can be attributed to inhomogeneous compositions (and resulting deviations in unit cell dimensions) of SnF2 and BaF2 according to Ba0.5±xSn0.5∓xF2 as well as amorphization of incorporated pristine materials.