The predicted energy landscape of XXXI at 0K from our calculations and the temperature dependent relative stability between forms A and B are reported in Figure (a), (b) and (c). Our calculations correctly predicted form B and the two disordered forms of form A among the top 25 predicted structures. The temperature dependent relative stability calculations indicate that with increased temperature form A, with its two disordered structures, become more stable as compared to form B, consistent with the experimental findings that form A is more stable at temperatures higher than 55°C. However, the relative free energy difference between the two forms at room temperature is small (about 0.4 kcal/mol), within the errors of the calculations, and therefore it can not be predicted with confidence which form is more stable at room temperature. It is also interesting to note that the relative lattice energy difference (stability at 0K reported in Figure (a)) among these three structures from our calculations are consistent with the results from all groups participating in seventh blind test that used similar DFT calculations to rank order the structures (including groups 3, 20), except for group 10 who reported a different order than others.