Atomic carbon

Atomic carbon in chemistry is single carbon atom with chemical formula :C: - in effect a dicarbene. 

This very short lived species is created by passing a large current through two adjacent carbon rods, generating an electric arc. Atomic carbon is generated in the process. Professor Phil Shevlin has done the principal work in the field based at Auburn University in the USA.

The way this species is made is closely related to the formation of fullerenes C₆₀, the chief difference being that a much lower vacuum is used in atomic carbon formation.

This species has been used to generate "true" carbenes by the abstraction of oxygen atoms from carbonyl groups:

R₂C=O + :C: → R₂C: + CO

Carbenes formed in this way will exhibit true carbenic behaviour. Carbenes prepared by other methods such as diazo compounds, might exhibit properties better attributed to the diazo compound used to make the carbene (which mimic carbene behaviour), rather than to the carbene itself. This is important from a mechanistic understanding of true carbene behaviour perspective.

References

• White G. J., Padman R. (1991). "Images of atomic carbon in the interstellar medium". Nature 354 (6354): 511–513. doi:10.1038/354511a0. 
• P. B. Shevlin (1972). "Formation of Atomic Carbon in the Decomposition of 5-tetrazoyldiazonium Chloride". J. Amer. Chem. Soc. 94 (4): 1379. doi:10.1021/ja00759a069. 
• P. B. Shevlin (1980). "The Preparation and Reaction of Atomic Carbon". In R. A. Abramovitch. Reactive Intermediates,. 1. New York: Plenum Press. p. 1. 
• M. J. S. Dewar, D. J. Nelson, P. B. Shevlin, K. A. Biesida (1981). "An Experimental and Theoretical Investigation of the Mechanism of Deoxygenation of Carbonyl Compounds by Atomic Carbon". J. Amer. Chem. Soc. 103 (10): 2802. doi:10.1021/ja00400a052. 
• Biesiada, Keith A.; Shevlin, Philip B. (1984). "Intramolecular trapping of an intermediate in the deoxygenation of a carbonyl compound by atomic carbon". The Journal of Organic Chemistry 49 (6): 1151. doi:10.1021/jo00180a047. 
• Moss, Robert A; Jones, Maitland (2004). "Atomic carbon". Reactive intermediate chemistry. pp. 463–500. ISBN 9780471233244. http://books.google.de/books?id=wp0C10qO0A8C&pg=PA463.