Fullerene, a molecule composed of carbon atoms that form a hollow, cagelike structure. The arrangement of the atoms produces pentagonal and hexagonal shapes—that is, shapes with five or six sides, respectively. Because of the structure's similarity to that of a geodesic dome, the molecules were named after the originator of such domes, R. Buckminster Fuller. A fullerene with 60 atoms appears almost spherical, and it has been nicknamed a buckminsterfullerene, or buckyball. The smallest type of fullerene contains 23 atoms.

Fullerenes are highly stable chemically and have a variety of unusual properties. Chemists have been able to add branches of other molecules to them, place atoms inside of them, and stretch them into rods and tubes. Fullerenes can be made to be magnetic, act as superconductors, serve as a lubricant, or absorb light.

Richard E. Smalley, Robert F. Curl, Jr., and Harold W. Kroto discovered fullerenes in 1985, in soot produced by vaporizing graphite with a laser. In 1992, fullerenes were found to occur naturally in certain kinds of rock.