The known crystal structures of urazole and maleic hydrazide are also predicted poorly by the force field calculations; their landscapes are provided in the SI (Figs. and). The three known polymorphs of maleic hydrazide lie between 5.74 and 7.83 kJ mol -1 above the global minimum, and the only known crystal structure of urazole lies 3.39 kJ mol -1 above than the global minimum. While the FIT+DMA force field has been suc- cessful for CSP of many small molecules, these three molecules were chosen as known failures, where it is clear that a higher level of theory is necessary for successfully ranking the crystal structures.