Structural Characteristics of Fullerenes

Abstract

Fullerenes, exemplified by the famous C60, all feature alluring closed cage-shaped structures composed of pentagons and hexagons. They are pure carbon clusters and also the molecular form of element carbon. Getting familiar with the structural characteristics of pristine fullerenes is essential for further understanding their properties. In this chapter, various important aspects regarding the fullerene structures are presented, including the fullerene polyhedra, fullerene duals, fullerene graphs, spiral algorithm, naming schemes, steric strain, cage stability, point-group symmetry, cage isomerization and cage interconversion, etc. Important rules such as the isolated pentagon rule and 2(N + 1)2 rule of spherical aromaticity are introduced. Then the detailed structural characteristics of a series of representative members in the big fullerene family are selectively shown. The involved cage size ranges from the smallest C20 to the supergiant C540. Some studies from both the experimental and theoretical sides are reviewed. Besides, different fullerene derivatives (endohedral and exohedral forms, heterofullerenes) and nonclassical fullerenes containing square or heptagon are also briefly mentioned. The illustrated various cage structures will present the readers a beautiful fullerene world.