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The discovery and identification new pictures from of carbon opens a window onto an uncharted world of materials with potential applications ranging from drug delivery to optics, superconductors, metals, and plastics.
Just as artist paints new pictures from the colors on their palettes, materials scientists seek to create new materials by forming new combinations of naturally existing elements. Trying to find a new element would be somewhat like trying to find a new primary color besides red, blue, or yellow.
Scientist don't expect to find a new element or molecular pattern that has never been seen before. Yet in 1985 two chemists, Harry Kroto of the University of Sussex and Richard Smalley of Rice University in Houston, made just such a discovery.
While visiting Smalley's lab, Kroto persuaded Smalley's research group to put carbon into Smalley's new device for exposing, materials laser beam. Although soot, composed of variable-sized clusters of carbon atoms, would have been the normally expected product, the researchers discovered an unexpected concentration of clusters that seemed to be quite stable. The material was certainly all carbon, but it behaved like neither graphite nor diamond, the only all-carbon materials then known.
Furthermore, it was huge, with a molecular weight (720) that required 60 carbon atoms (12 * 60 = 720). The researchers were then challenged to imagine how 60 atoms could form a stable unit, since the only proven models of stable multicarbon units were chains of carbon atoms and 5-or 6-atom rings of carbon atoms. Yet neither rings nor chains could be stable with so many atoms.
After considerable thought, and discussions with students and colleagues, Smalley imagined that perhaps the mysterious cluster was actually a 60-carbon molecule forming a hollow sphere. His efforts to model a 60-atom hollow sphere finally produced a stable configuration formed by combining 5-atom and 6-atom rings. Upon checking with a colleague in math, Smalley learned that he had "discovered" the basic soccer-ball shape.
The shape was also identical to that of the geodesic dome popularized by inventor R. Buck Minister Fuller during the 1950s. Smalley and Kroto published their hypothesized structure for C60 in 1985 and could not resist naming their discovery buckminsterfullerene, which has since been shortened to fullerene, or "buckyball"
Further development of the field was stymied by the inability to make the 60-atom carbon in quantities sufficient for detailed structural analysis. Then in 1990, the field was broken open by physicist Donald Huffman of the University of Arizona and Wolfgang Kratschmer of the Max Plank Institute for Nuclear Physics in Heidelberg, Germany Huffman and Kratschmer jointly discovered a carbon-arc method for producing fullerenes in multigram quantities. With these quantities they were able to determine the structure of the mystery carbon-- indeed, the 60-atom carbon molecule did have a soccer-ball-like structure.
Scientists eventually applied conventional chemical symbolism to the Smalley-Kroto fullerene, and most now call it c60. Huffman and Kratschmer also found that the graphite soot formed in a vacuum
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