Structure and stability of substitutional metallofullerenes of the first-row transition metals

A DFT investigation of substitutional metallofullerenes MC59 (M = Sc-Ni) shows that they are drop-shaped, with the deviation from spherical structure depending on the size of the metal atom. The metal atomic radius, however, seems to be unimportant for the stability of the metallofullerenes. In general, the stability increases toward the right-hand side of the transition series, commensurate with the higher electronegativities of the late transition metals. CrC59 is calculated to be more stable than the metallofullerenes of manganese and iron, suggesting that future observation of CrC59 may be anticipated.