A form of carbon composed of clusters of 60 carbon atoms bonded together in a polyhedral structure composed of pentagons and hexagons (see illustration). Originally it was identified in
1985 in products obtained by firing a high-power laser at a graphite target.
It can be made by an electric arc struck between graphite electrodes in an inert atmosphere. The molecule, C₆₀, was named after the US architect Richard Buckminster Fuller (1895–1983) because of the resemblance of the structure to the geodesic dome, which Fuller invented. The molecules are informally called buckyballs; more formally, the substance itself is also called fullerene.
The substance is a yellow crystalline solid (fullerite), soluble in benzene. Various fullerene derivatives are known in which organic groups are attached to carbon atoms on the sphere. In addition, it is possible to produce novel enclosure compounds by trapping metal ions within the C₆₀ cage. Some of these have semiconducting properties.
The electric-arc method of producing C₆₀ also leads to a smaller number of fullerenes such as C₆₀, which have less symmetrical molecular structures. It is also possible to produce forms of carbon in which the atoms are linked in a cylindrical, rather than spherical, framework with a diameter of a few nanometres. They are known as buckytubes (or nanotubes).