fullerene

fullerene, any of a class of carbon molecules in which the carbon atoms are arranged into 12 pentagonal faces and 2 or more hexagonal faces to form a hollow sphere, cylinder, or similar figure. The smallest possible fullerene molecule may have as few as 32 atoms of carbon, although fullerenelike molecules (lacking a hexagonal face) with as few as 20 carbon atoms have been found.

The most common and most stable fullerene is buckminsterfullerene, a spheroidal molecule, resembling a soccer ball, consisting of 60 carbon atoms. Buckminsterfullerene is the most abundant cluster of carbon atoms found in carbon soot. It is also the smallest carbon molecule whose pentagonal faces are isolated from each other. Other fullerenes that have been produced in macroscopic amounts have 70, 76, 84, 90, and 96 carbon atoms, and much larger fullerenes have been found, such as those that contain 180, 190, 240, and 540 carbon atoms.

Fullerenes were first identified in 1985 as products of experiments in which graphite was vaporized using a laser, work for which R. F. Curl, Jr., R. E. Smally, and H. W. Kroto shared the 1996 Nobel Prize in Chemistry. Fullerenes have since been discovered in nature as a result of lightning strikes, in the residue produced by carbon arc lamps, in interstellar dust, and in meteorites.

Fullerene chemistry involves substituting metal atoms for one or more carbon atoms in the molecule to produce compounds called

fullerides. Among these are conducting films of alkali metal-doped fullerenes and superconductors (potassium-doped T_c 18°K;, rubidium-doped T_c 30°K;). Fullerenes also have been used to produce tiny diamonds and thin diamond films. Fullerene research is expected to lead to new materials, lubricants, coatings, catalysts, electro-optical devices, and medical applications.

Bibliography

See M. S. Dresselhaus et al., Science of Fullerenes and Carbon Nanotubes (1996); H. W. Kroto, The Fullerenes: New Horizons for the Chemistry, Physics, and Astrophysics of Carbon (1997); R. Taylor, ed., Lecture Notes on Fullerene Chemistry (1999).

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fullerene

Any of a class of all-carbon molecules whose atoms are arranged in closed hollow shells. Allotropes of carbon first identified in 1985, they have varying (but even) numbers of atoms bonded into structures having 12 pentagonal and 2 or more hexagonal faces. Fullerenes comprising dozens to hundreds of carbon atoms have been prepared. The best known and most stable fullerene, buckminsterfullerene (C₆₀, nicknamed buckyball), has 60 carbon atoms arranged in a pattern like that on a standard soccer ball. It is named for R. Buckminster Fuller, whose geodesic dome designs its structure resembles. Chemists have made fullerene derivatives (e.g., with attached hydrogen or halogen atoms or organic groups; see functional group) and have prepared doped fullerenes (e.g., with alkali metal atoms such as potassium; see dopant) that show superconductivity at relatively high temperatures. One or more metal or noble-gas atoms can be trapped in the molecule's hollow interior, resulting in unique complexes called endohedral fullerenes.