C60 can be hydrogenated, suggesting that a modified buckminsterfullerene called organometallic buckyballs (OBBs) could become a vehicle for "high density, room temperature, ambient pressure storage of hydrogen". These OBBs are created by binding atoms of a transition metal (TM) to C60 or C48B12 and then binding many hydrogen atoms to this TM atom, dispersing them evenly throughout the inside of the organometallic buckyball. The study found that the theoretical amount of H2 that can be retrieved from the OBB at ambient pressure approaches 9 wt %, a mass fraction that has been designated as optimal for hydrogen fuel by the U.S. Department of Energy.