1. Discovery and Initial Characterization (1985):
* Harold Kroto, Robert Curl, and Richard Smalley at Rice University accidentally discovered C60 while experimenting with a laser vaporization technique. They observed a new molecule with a mass-to-charge ratio consistent with 60 carbon atoms.
* Early spectroscopic data (mass spectrometry, infrared spectroscopy) hinted at a highly symmetrical structure but didn't provide a definite shape.
2. Theoretical Predictions (1985):
* Eiji Osawa and other theoretical chemists proposed the truncated icosahedron structure for C60, a shape resembling a soccer ball.
* This theoretical prediction was based on Hückel theory, which explained the stability of aromatic compounds, and the known tendency of carbon atoms to form three-dimensional structures.
3. Experimental Confirmation (1990-1991):
* Wolfgang Krätschmer and Donald Huffman developed a method for producing macroscopic quantities of C60 using an electric arc discharge. This breakthrough allowed scientists to study the molecule in detail.
* X-ray diffraction studies on crystalline C60 confirmed the truncated icosahedral structure, solidifying the football-like shape.
* Nuclear magnetic resonance (NMR) spectroscopy also provided evidence for the symmetry and carbon atom connectivity within the molecule.
In summary, the confirmation of C60's formula and shape involved a combination of:
* Accidental discovery: Initially observed using mass spectrometry and other spectroscopic techniques.
* Theoretical prediction: Based on chemical principles and Hückel theory, the truncated icosahedron structure was proposed.
* Experimental validation: X-ray diffraction and NMR spectroscopy provided definitive evidence for the structure.
This collaborative effort involving experimentalists, theorists, and computational chemists solidified the understanding of this unique and intriguing molecule.
