Fullerenes

Until the mid 1980's, pure carbon was thought to exist in two forms: graphite and diamond. The discovery of C₆₀ molecules in interstellar dust in 1985 added a third form to this list. The existence of C₆₀, which resembles a soccer ball, had been hypothesized by theoreticians for many years. In the late 1980's synthetic methods were developed for the synthesis of C₆₀, and the ready availability of this form of carbon led to extensive research into its properties.

Figure 1.1 : Example of fullerenes: a buckyball (C60 on left and an extended bucktube).

The C₆₀ molecule (Figure 1.1 ; left), is called buckminsterfullerene, though the shorter name fullerene is often used. The name is a tribute to the American architect R. Buckminster Fuller, who is famous for designing and constructing geodesic domes which bear a close similarity to the structure of C₆₀. As is evident from the display, C₆₀ is a sphere composed of six-member and five-member carbon rings. These balls are sometimes fondly referred to as "Bucky balls". It should be noted that fullerenes are an entire class of pure carbon compounds rather than a single compound. A distorted sphere containing more than 60 carbon atoms have also been found, and it is also possible to create long tubes (Figure 1.1; right). All of these substances are pure carbon.