The absence of interlayer movement is attributed to the structural constraints imposed by the MnO6 octahedra, which act as barriers to ion transport along the c-axis (Figure ). To quantify the dynamics of the atomic species within the system, the mean squared displacement (MSD) was calculated for all atoms based on the NVT simulation results (Figure ). The MSD data showed that only fluoride ions exhibit long-range diffusion within the conditions explored in this study, while all other atomic species are restricted to thermal vibrations around their crystallographic positions. Among the immobile species, as expected, oxygen ions displayed the highest thermal motion. The cations exhibited comparatively lower thermal motion, with manganese, located at the center of the MnO6 octahedra, showing the least movement due to the stabilizing influence of its octahedral coordination. Strontium and lanthanum, which share the same crystallographic site, exhibited slight differences in their thermal motion. Strontium, being lighter than lanthanum, demonstrated slightly higher thermal vibrations, consistent with its lower mass. The diffusion coefficient of fluoride ions at the operating temperature was calculated by linearly interpolating the MSD vs time plot, according to the following equation: