Buckminsterfullerene 1: introduction

Buckminsterfullerene has the formula C₆₀ and a structure analogous to a typical black and white football. It is an allotrope of carbon, and distinct from diamond and graphite in being molecular. It was discovered in 1985 and is named after Richard Buckminster Fuller, the architect of geodesic domes.

Since its discovery a whole range of carbon molecules have been identified, even in candle soot; they are collectively known as fullerenes. They range from icosahedral C₂₀ up to molecules with hundreds of carbon atoms. Further investigation has led to synthesis of these molecules and so-called carbon nanotubes - making use of the fact that the introduction of pentagons into planar sheets of hexagons introduces curvature. Carbon nanotubes have much promise as materials due to their great strength.

C₆₀ has icosahedral symmetry - the highest symmetry possible for a molecule. It is a truncated icosahedron, having 12 pentagonal faces (at the sites of truncation) and 20 hexagonal faces, where none of the pentagons is in contact with any other pentagon. It is an Archimedean solid (like the cuboctahedron - see copper) and as such all the carbon atoms are in equivalent positions. It was a revelation for its discoverers that a molecule with 60 carbon atoms could produce just a single peak in its carbon-13 NMR spectrum. All carbon atoms are bonded to three other carbons, as in graphite, but there is less electron delocalisation due to the curvature of the surface. It has been shown mathematically that there are 1812 isomers of C₆₀.

Go to page 2 to look at the unit cell within the bulk structure of Buckminsterfullerene.

Page 2