All VASP calculations were performed using the PBE exchange correlation function with the GD3BJ dispersion correction. The projector augmented wave method was used for all VASP calculations with the standard supplied pseudopotentials. Following this optimization, a more stringent removal of duplicates was carried out by using the COMPACK algorithm for all structures within 10 kJ mol -1 of the global energy minimum for each CSP, irrespective of the space group of each structure.