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The story of buckyballs

Buckminsterfullerene looks like a soccer ball because of its pattern of 20 hexagons and 12 pentagons.

Buckminsterfullerene, a sixty carbon soccer ball-shaped molecule, was discovered, named, and its structure deciphered over a ten day period of hectic activity by five scientists at Rice University in 1985.  Three of these, Harry Kroto, Richard Smalley and Robert Curl, shared a Nobel Prize for its discovery in 1996.  The story of the "buckyball" is an illustration of Louis Pasteur's famous observation that chance favors the prepared mind.

Harry Kroto is a British chemist with a wide-angled worldview—he has a voracious curiosity that occasionally draws him far afield of the chemistry lab. In the early eighties, he and his students were engaged in making long chain carbon/ nitrogen molecules for the purpose of watching them bend and rotate. At around the same time, various carbon chains were discovered floating around in interstellar space. Kroto could recognize the spectroscopic signature of his creations, and he was able to persuade an astrophysicist friend to search for his compounds in space. Sure enough, they were hanging out in a cloud around Taurus, in far greater concentration than existing theory could accommodate. One possible explanation was that red giant carbon stars were churning out Kroto's molecules and other organic constituents of a prebiotic primal soup.

Kroto couldn't exactly replicate a carbon star in his laboratory, but he thought that the next best thing was a laser-vaporization supersonic cluster beam apparatus found in the Houston lab of a recent acquaintance, Richard Smalley. The plan was to blast a graphite disc with the laser and analyze the resultant carbon compounds formed. Sure enough, carbon chains of the 6 to 8 carbon size that Kroto was looking for were indeed created, along with even longer chains. But there was an annoying by-product that appeared to have an unheard of 60 carbons.  If the procedure was optimized, the C-sixty band was practically the only thing formed. 

What could it be? Model-building began in earnest, not with sophisticated computers seeking the best fit, but first with toothpicks and jelly beans, than later with paper cut-outs of hexagons and pentagons, exactly the sort of brainstorming that allowed Watson and Crick to guess the structure of DNA.  The solution to the puzzle hinged on an earlier visit by Kroto to Montreal's Expo '67 where he had viewed one of Buckminster Fuller's domes, hence the name. 

Buckminsterfullerene is a beautiful thing, with absolute symmetry. Every carbon is bound to three others, at the vertex of one pentagon and two hexagons. A nuclear magnetic resonance spectrum of the molecule reveals a single band. 

The buckyball is the prototype of a whole class of carbon molecules referred to collectively as fullerenes. One example is the carbon nanotube, which has gained considerable commercial interest because of its exceptional tensile strength and electrical and heat conductive properties. Nanotubes and cage-like fullerenes also have potential as components in molecular machines the size of proteins.

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Buckminsterfullerene looks like a soccer ball because of its pattern of 20 hexagons and 12 pentagons.
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