Although the experimental structure was predicted to have higher energy than a few other predicted structures at 0K, its relative stability improved substantially with increased temperature (Figure (c) in SI). At room temperature, the rank I predicted structure and the experimental structure have a free energy difference of about 0.3 kcal/mol while all other predicted structures have higher free energies. These results highlight the important role of entropy in accurately evaluating the relative stabilities of crystal structures at room temperature.