DFT study on the stabilities of the heterofullerenes [Sc.sub.3]N@[C.sub.67]B, [Sc.sub.3]N@[C.sub.67]N, and [Sc.sub.3]N@[C.sub.66]BN

Density functional theory (DFT) calculations are used to investigate the relative stabilities of all isomers of [Sc.sub.3]N@[C.sub.67]B and [Sc.sub.3]N@[C.sub.67]N as well as those of stable isomers of [Sc.sub.3]N@[C.sub.66]BN. It is concluded that the relative stabilities of various isomers of the BN-substituted fullerenes are understood in terms of the combined electrostatic effects in the B- and N-substitutions of [Sc.sub.3]N@[C.sub.68] complemented by a specific local preference in the N-substitution and the formation of a B-N bond.