To validate our structural model, we generated larger TiOF 2 structures (4 × 4 × 4 supercells) using a structureprediction genetic algorithm (GA). Our genetic algorithm used a combination of elitist and proportionate selection, with selection probabilities based on a Boltzmann fitness function and energies of competing configurations calculated using our DFT-derived cluster expansion model. Full details of this genetic algorithm are provided in the Supporting Information.