Transitioning to the distorted octahedral environment encountered in the rhombohedral (R 3) PB variant. Due to Prussian blue being a double perovskite type material and octahedral tilting in Perovskites being extensively studied, it is known that a phase of this symmetry has to be formed by a cooperative out-of-phase rotation of the FeC 6 and FeN 6 octahedra in all three directions of space (a -a -a -rotation after Glazer). Such a rotation often causes the trigonal distortion, which further splits the d-orbitals by forming one a 1g and two e g states out of the already favourable t 2g -states. The a 1g state is further lowered in energy in comparison to both the barycenter and the t 2g -states. The e g states therefore have to increase in energy compared to the t 2g -states, but they still will be lower than the overall barycenter energy.