Chemists make first-ever ring of pure carbon
> Gawel and his collaborators have now created and imaged the long-sought ring molecule carbon-18. Using standard ‘wet’ chemistry, his collaborator Lorel Scriven, an Oxford chemist, first synthesized molecules that included four-carbon squares coming off the ring with oxygen atoms attached to squares. The team then sent their samples to IBM laboratories in Zurich, Switzerland, where collaborators put the oxygen–carbon molecules on a layer of sodium chloride, inside a high-vacuum chamber. They manipulated the rings one at a time with electric currents (using an atomic-force microscope that can also act as a scanning-transmission microscope), to remove the extraneous, oxygen-containing parts. After much trial-and-error, micrograph scans revealed the 18-carbon structure. “I never thought I would see this,” says Scriven.The molecule (an all-carbon cycle of 18 atoms) was prepared in a very unusual way - by directly manipulating the atoms using an atomic force microscope.In other words, each molecule is made individually. This is not the way that chemists typically work, and will not result in quantities of material that can be seen.The abstract says nothing about chemical stability, but I suspect C-18 quite unstable and may never be prepared in gram quantities.Higher cycles containing more carbons may be more stable, but this is likely to remain a curiosity for some time.Still, this is a new kind of "allotrope" of carbon. The cyclic, relatively rigid nature of the structure and the potential for electrons to circulate under applied fields could lead to some unusual applications.