We also use this stoichiometry to denote the Ca concentrations x considered in this computational study as it avoids ambiguity associated with the 0.5 occupancies when discussing the differently occupied systems at the high vacancy limit. In the y= 0.5 occupancy are three cations to be distributed among six distinct sites, which are all equal in energy for a single occupancy within the rhombohedral unit cell, yielding 20 possible distinct occupation patterns inside the unit cell. However, the variation in the mutual distances between the three cations depending on the particular distribution leads to a variation in the interaction strength causing an energetic ordering of these symmetrically inequivalent occupation patterns. Our calculations showed that the occupation patterns, where alternating sites along the z axis are occupied are the most stable. This is most likely due to their maximum distance between the cations. They are closely followed in stability by the systems in which two neighboring sites are occupied and the most unstable variations are present when the cations sit right next to each other. However, these stabilities vary by less than 5 meV per atom (see Tab. 1) and suggest that the preference for the cations to be spread equally inside In order to verify the most stable configurations, we employed a larger 2×2×1 super cell for the NASICON structure. Initially, various occupation scenarios were randomly selected as well as the options with the highest symmetry. Those were cells with altering layers fully filled as well as neighboring layers fully filled. In total 95 potential occupation arrangements were investigated. Within this context, the cations exhibited a preference for repeatedly occupying the same site within in neighboring unit cells, which led to the formation of distinct layers. Among these configurations, the most stable arrangement involved three layers that were fully occupied while their alternating three layers remained entirely empty.