Fullerenes are molecules made only of carbon atoms joined in rings, forming hollow shapes such as spheres and tubes. A C60 molecule has 60 carbon atoms joined by covalent bonds in a hollow sphere. Each carbon atom forms three covalent bonds, as in graphite.
C60 is a simple molecular substance. The atoms inside each molecule are held by strong covalent bonds, but the molecules are attracted to each other only by weak intermolecular forces. Little energy is needed to overcome these forces, so C60 has a much lower melting point than diamond or graphite, and it is soft.
Graphene is a single layer of graphite, so it is one atom thick. Each carbon atom is bonded to three others in a flat sheet of hexagons. The strong covalent bonds make graphene very strong, and because it is so thin it is also very light. Each carbon atom has one delocalised electron that is free to move, so graphene conducts electricity well.
