从富勒烯笼五六元环的分布情况评述了内包单金属、双金属、三金属以及三金属氮化物(M3N)和碳化物(M2C2)富勒烯C66~C84团簇的结构特征。富勒烯满足五元环最大分离规则,内包不同类型的金属团簇不仅改变了笼的稳定性顺序,也使C66、C68、C70、C72、C74、C78和C84的部分异构体违背五元环最大分离规则。
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.