DEVELOPING AND DESIGNING NEW CHEMICALS AND MATERIALS - Chemistry: Notable Research and Discoveries - page 13

eter to identify the molecules; a mass spectrometer splits molecules into
charged fragments, uses magnetic fields to measure the charge-to-mass
ratio of the fragments, and sums up the masses to specify the original
molecule. One of the main goals of the experiments was to study stellar
chemistry, but then the researchers discovered to their surprise a mol-
ecule of carbon containing 60 atoms—C 60 .
Such a large number of atoms could possibly adopt any one of a
number of different arrangements. No one previously knew that pure
carbon could assume another form other than graphite and diamond,
but as other researchers carefully examined carbon sources such as soot
(the remains of combustion), they found some C 60 . In the early 1990s,
curious scientists examined the structure of C 60 using nuclear magnetic
resonance (NMR) spectroscopy. Unlike X-ray crystallography, NMR
spectroscopy does not require crystallization of the material. The pro-
cess involves quantum mechanics, but in simple terms, it begins with
a strong magnetic field to align the atoms of a sample of the material.
Atoms respond to radio waves differently depending on their position
in the molecule, and researchers map the molecule by transmitting and
detecting these low-frequency electromagnetic waves. The technique is
similar to magnetic resonance imaging (MRI), used by physicians to
image a patient's body. NMR spectroscopy is often easier than X-ray
crystallography but only works for certain molecules, and it generally
produces a fuzzier picture.
NMR spectroscopy results suggested a soccer ball-shaped struc-
ture, as illustrated in the figure. Proof of this structure came in 1991,
when Joel M. Hawkins, Frederick J. Hollander, and their colleagues
at the University of California, Berkeley, crystallized C 60 and studied
it with X-ray crystallography. This technique, which generally offers
exceptionally high resolution, confirmed the astonishing soccer ball
frame.
C 60 was named buckminsterfullerene, in honor of the visionary
American architect Richard Buckminster Fuller (1895-1983). Fuller
is known for developing and promoting the geodesic dome, which C 60
resembles. (Buckminsterfullerene molecules are also sometimes called
buckyballs.) Later, researchers discovered this molecule belongs to a
family of related carbon structures, which have become known as fuller-
enes. The smallest fullerene is C 20 , containing 20 carbon atoms.