Structural characteristics of endohedral metalofullerenes ranging from C66 to C84

As the size of the fullerene cage increases, the possibility for the existence of multiple isomers also increases. Most fullerenes and endohedral fullerenes obey the isolated pentagon rule (IPR), which requires that each of the twelve pentagons in the carbon cage be surrounded by hexagons. Non-IPR structures have already been isolated for cages containing 66, 68, 70, 72, 74, 78 or 84 carbon atoms. The structural characteristics of the endohedral metallofullerenes, which consist of carbon cages from C66 to C84 and encaged species including one, two, three atoms, metal nitrides(M3N) or metal carbides(M2C2) are illustrated.