By the DC arc-discharge of graphite rods doped with other substances in He and NH3 mixing gas,higher endohedral metallofullerenes(EMFs) were synthesized in a high yield. This lays the foundation for the separation,purification and further study of higher EMFs. The doped materials act as heat carriers and at the same time catalyze the growth of higher EMFs,whereas NH3 suppresses the formation of fullerenes such as C60 and C70,etc.
