To validate the predictions from our 6 × 6 × 6 GA structure prediction, we performed additional DFT calculations on a set of [O-F-F-O] ordered 3 × 3 × 3 TiOF 2 supercells and compared the resulting energies (per formula unit) to the energies of those of the 2 × 2 × 2 supercells in our CE training set with exclusive cis-TiO 2 F 4 cation coordination and to the DFT-optimised energies of our four 4 × 4 × 4 GA-predicted supercells. All three sets of structures have no collinear O-Ti-O units and, there-