The first calculation, using our GA-structureprediction scheme, yielded a 6 × 6 × 6 supercell with the same local coordination preferences as for the GApredicted 4×4×4 supercells. The resulting structure contains no collinear O-Ti-O units, and the TiX 6 coordination octahedra are predominantly cis-TiO 2 F 4 (89.8 %), with small proportions of fac-TiO 3 F 3 (5.1 %) and TiOF 5 (5.1 %). This distribution of TiO x F 6-x coordination octahedra differs significantly from that predicted by mapping the Brink et al. ] anion sequences (23.1 %) is higher than that expected for an equivalent supercell with a fully random arrangement of anions (6.6 %). We attribute this effect to a second-order consequence of the short-range ordering in TiOF 2 , where collinear O-Ti-O units are strongly disfavoured, resulting in (partial) anion correlations at intermediate length scales.