Both the simulated PDF and 19 F NMR spectra show good agreement with the corresponding experimental data, with particularly good agreement in the case of the PDF data for GA-predicted structure 4. We therefore conclude that our DFT-derived cluster expansion model correctly describes the form of anion short-range order in ReO 3 -type TiOF 2 , and consider structure 4, obtained from our genetic algorithm structure prediction, as a representative structural model for the experimental samples considered in this work.