We observed linear correlation between both ∆G sol (ODCB) and ∆G sol (water) with the size of fullerene cage; larger sizes correspond to lower solvation energies (Figure )). Previous studies have also found that the solvation free energies of carbon allotropes, including C 60 and carbon nanotubes, exhibit a negative linear correlation with their surface area. The correlation between solvation free energy and geometric measures will be addressed in section 3.2.2.