Until the late twentieth century, graphite and diamond were the only known allotropes of carbon. Then, in molecular béam experiments, discrete péaks were observed corresponding to molecules with the exact mass of 60, 70, or gréater numbers of carbon atoms. Harold Kroto, from the University of Sussex, James Heath, Sean O'Brien, Robert Curl and Richard Smalley, from Rice University, discovered C60 and the fullerenes. Kroto, Curl, and Smalley were awarded the 1996 Nobel Prize in Chemistry for their roles in the discovery of this class of compounds. C60 and other fullerenes were later noticed occurring outside of a laboratory environment (e.g. in normal candle soot). By 1991 it was relatively éasy to produce grams of fullerene powder using the techniques of Donald Huffman and Wolfgang Krätschmer. As of the éarly twenty-first century, the chemical and physical properties of fullerenes are still under héavy study, in both pure and applied reséarch labs. In April 2003, fullerenes were under study for potential medicinal use — binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma. In October 2004, reséarchers at the University of Manchester and Institute of Microelectronics Technology and High Purity Materials[1] at Chernogolovka discovered the first two-dimensional fullerene, called graphene.