Carbon trioxide

The C_s, D_3h, and C_2v isomers of carbon trioxide.

Carbon trioxide (CO₃) is an unstable oxide of carbon (an oxocarbon). Three possible isomers of carbon trioxide, with molecular symmetry point groups C_s, D_3h, and C_2v, have been most studied by theoretical methods, and the C_2v state has been shown to be the ground state of the molecule.^[1][2]

Carbon trioxide should not be confused with the stable carbonate ion (CO₃²⁻).

Carbon trioxide can be produced, for example, in the drift zone of a negative corona discharge by reactions between carbon dioxide (CO₂) and the atomic oxygen (O) created from molecular oxygen by free electrons in the plasma.^[3]

Another reported method is photolysis of ozone O₃ dissolved in liquid CO₂, or in CO₂/SF₆ mixtures at -45 °C, irradiated with light of 2537 Å. The formation of CO₃ is inferred but it appears to decay spontaneously by the route 2CO₃ → 2CO₂ + O₂ with a lifetime much shorter than 1 minute.^[4]

Carbon trioxide can be made by blowing ozone at dry ice (solid CO₂), and it has also been detected in reactions between carbon monoxide (CO) and molecular oxygen (O₂).

References

1. Tim Kowalczyk, Electronic structure and spectroscopy of carbon trioxide
2. T. Kowalczyk; A. I. Krylov (Aug 2007). "Electronic structure of carbon trioxide and vibronic interactions involving Jahn-Teller states". J. Phys. Chem. A. 111 (33): 8271–8276. doi:10.1021/jp073627d. ISSN 1089-5639. PMID 17661455.
3. Sabin, J. R; Kim, H (1971). "A theoretical study of the structure and properties of carbon trioxide". Chemical Physics Letters. 11 (5,): 593–597. Bibcode:1971CPL....11..593S. doi:10.1016/0009-2614(71)87010-0.
4. DeMore W. B.; Jacobsen C. W. (1969). "Formation of carbon trioxide in the photolysis of ozone in liquid carbon dioxide". Journal of Physical Chemistry. 73 (9): 2935–2938. doi:10.1021/j100843a026.

Further reading

• Electronic structure and spectroscopy of carbon trioxide
• Sobek V.; Skalný J. D. (1993). "A simple model of processes in the drift region of negative corona discharge in a mixture of air with halocarbons". Czechoslovak Journal of Physics. 43 (8): 807. Bibcode:1993CzJPh..43..807S. doi:10.1007/BF01589802.
• Pople J. A.; Seeger U.; Seeger R.; Schleyer P. v. R. (2004). "The structure of carbonate". Journal of Computational Chemistry. 1 (2): 199–203. doi:10.1002/jcc.540010215.
• Moll N. G.; Clutter D. R.; Thompson W. E. (1966). "Carbonate: Its Production, Infrared Spectrum, and Structure Studied in a Matrix of Solid CO₂". The Journal of Chemical Physics. 45 (12): 4469–4481. Bibcode:1966JChPh..45.4469M. doi:10.1063/1.1727526.
• Gimarc B. M.; Chou T. S. (1968). "Geometry and Electronic Structure of Carbon Trioxide". The Journal of Chemical Physics. 49 (9): 4043–4047. Bibcode:1968JChPh..49.4043G. doi:10.1063/1.1670715.
• DeMore W. B.; Dede C. (1970). "Pressure dependence of carbon trioxide formation in the gas-phase reaction of O(1D) with carbon dioxide". Journal of Physical Chemistry. 74 (13): 2621–2625. doi:10.1021/j100707a006.
• Francisco J. S.; Williams I. H. (1985). "A theoretical study of the force field for carbon trioxide". Chemical Physics. 95 (3): 373. Bibcode:1985CP.....95..373F. doi:10.1016/0301-0104(85)80160-9.