Equilibrium geometries and stabilities of endohedral complexes formed by H, Li, Na, K, Be, Mg, Ca and D 5 h C50, as well as their charged states, are computed using B3LYP/6-31G* method, and bond lengths of H@C50 are nearly unchanged compared with those of bare C50, indicating interaction between them is almost negligible. However, C–C bonds change significantly when metals are encapsulated. Following the increase of the extra charges on the complexes, the structural distortions decrease for Li, Na, K, Mg, and Ca series endohedral derivatives, but increase for Be series endohedral derivatives, which change in the same way with C50 → → . Most endohedral complexes investigated are energetically favorable, except for H@C50, Be@C50, and Mg@C50. E HOMO and E LUMO are nearly unchanged when atoms are encapsulated, but significantly decrease following the increase of extra positive charges, and both are determined by the number of extra charges. Frequency calculations show that K@ and Be@ are local minima. The D 3 endohedral complexes are optimized for comparison, and their structural and energetic parameters change in the same tendency with these of D 5 h isomers. Only D 3 K@C50 is a local minimum, and the D 3 complexes are not necessarily more stable than the corresponding D 5 h isomers.