With these structures, we performed full geometry optimisation using DFT calculations, producing the two structures shown in Fig. (a-b), details of which are in Section. S3.2. We then compared the similarity of the fully optimised structure of the P 3 crystal structure to the experimentally reported structure using COMPACK. For an overlay of 15 molecules excluding hydrogens, a RMSD = 0.234 Å was observed (Fig. ). To determine which one was more energetically stable, we compared the energies of the two structures and found the P 3c1 structure was 3.2 kJ mol -1 higher in energy than P 3. This energy difference is on the order of error for the DFT calculations and thus considered negligible, evidencing that our coarse-grained model that only considered nearest neighbour interactions was able to accurately encapsulate the thermodynamic phase behaviour of B11.