Discovery of Buckyballs

A buckyball (short for buckminsterfullerene, a term we explain shortly) is a molecule containing 60 carbon atoms. Each carbon atom is bonded to three adjacent carbon atoms, just as in graphite. However the carbon atoms in a buckyball form a teensy-weensy sphere that’s about 1 nanometer in diameter, as shown in Figure 4-3. Because one of the properties of carbon atoms is that they can bond to many other types of atoms, researchers can use them to create customized molecules, useful in various applications discussed throughout this book.

Desperately seeking buckyballs

Buckyballs were discovered through an interesting collaboration of researchers from two universities. Richard Smalley at Rice University was studying semiconductor materials. He had a device that shined a laser at a solid sample, vaporized part of it, and analyzed the clusters of atoms that formed in the vapor. Meanwhile, at the University of Sussex, Harry Kroto was attempting to reproduce a material found in deep space that generated specific molecular spectra from carbon atoms. Bob Curl, also from Rice University, was doing similar work. Curl ran into Kroto at a symposium and suggested he drop by Rice University because Smalley’s scientific instrumentation might be helpful in his work. Kroto dropped by Rice, and after seeing the work that Smalley was doing, he became interested in using that equipment to reproduce his carbon molecules. Time spent working with high-end scientific equipment is always at a premium, so Kroto had to wait about a year until the equipment was available. In August of 1985, Smalley, Kroto, Curl, and some graduate students performed a series of experiments producing carbon molecules and clusters. They found that under certain conditions, most of the molecules generated contained 60 carbon atoms. Voilà: buckyballs.

While many of the atoms in buckyballs are connected together in hexagons (just as in graphite sheets), some of the atoms are connected together in pentagons. The pentagons allow the sheet of carbon atoms to curve into the shape of a sphere. Every buckyball surface contains 12 pentagons and 20 hexagons.

After much discussion and modeling, researchers determined that 60 carbon atoms form a single stable molecule only if they’re arranged in 20 hexagons and 12 pentagons that are linked to form a sphere — as it happens, it’s the same arrangement of hexagons and pentagons proposed by American architect and engineer Buckminster Fuller for his famed geodesic dome. No wonder these molecules got dubbed buckminsterfullerenes (that’s fullerenes for short) in his honor. This type of spherical carbon molecule has been found in various other sizes. The fullerene family of molecules is often identified by the letter C followed by the number of carbon atoms, for example C60, C70, C80.

Excerpted from Nanotechnology For Dummies (1st edition) by Richard Booker and Earl Boysen

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