Carbon trioxide

For polyatomic ion CO²⁻
₃, see Carbonate. For the UK postal district, see CO postcode area.

Carbon trioxide (CO₃) is an unstable oxide of carbon (an oxocarbon). The possible isomers of carbon trioxide include ones with molecular symmetry point groups C_s, D_3h, and C_2v. The C_2v state, consisting of a dioxirane, has been shown to be the ground state of the molecule.^[1] Carbon trioxide should not be confused with the stable carbonate ion (CO²⁻
₃).

Carbon trioxide

The Cs, D3h, and C2v isomers of carbon trioxide
Names
IUPAC names Carbon trioxide C2v isomer: Dioxiran-3-one D3h isomer: Carbonate radical
Systematic IUPAC name C2v isomer: Peroxycarbonic anhydride D3h isomer: Trioxidocarbon(2•)
Other names Cs isomer: Oxidooxymethanone Peroxycarbonite radical
Identifiers
CAS Number	12144-05-7
3D model (JSmol)	Cs: Interactive image D3h: Interactive image C2v: Interactive image
PubChem CID	19817254
InChI InChI=1S/CO3/c2-1-3-4-1 Key: NPDDCAZCWJWIBW-UHFFFAOYSA-N
SMILES Cs: O=[C]O[O] D3h: O=C([O])[O] C2v: O=C1OO1
Properties
Chemical formula	CO3
Molar mass	60.008 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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.^[2] Another reported method is photolysis of ozone O₃ dissolved in liquid CO₂, or in CO₂/SF₆ mixtures at −45 °C, irradiated with light of 253.7 nm. The formation of CO₃ is inferred but it appears to decay spontaneously by the route

2 CO₃ → 2 CO₂ + O₂

with a lifetime much shorter than 1 minute.^[3] 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). Along with the ground state C_2v isomer,^[4] the first spectroscopic detection of the D_3h isomer was in electron-irradiated ices of carbon dioxide.^[5]

References

1. 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. Bibcode:2007JPCA..111.8271K. doi:10.1021/jp073627d. ISSN 1089-5639. PMID 17661455.
2. 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.
3. 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.
4. Bennett, Chris J.; Jamieson, C.; Mebel, Alexander M.; Kaiser, Ralf I. (2004). "Untangling the formation of the cyclic carbon trioxide isomer in low temperature carbon dioxide ices". Physical Chemistry Chemical Physics. 6 (4): 735. Bibcode:2004PCCP....6..735B. doi:10.1039/b315626p. S2CID 51769127.
5. Jamieson, Corey S.; Mebel, Alexander M.; Kaiser, Ralf I. (2006). "Identification of the D_3h Isomer of Carbon Trioxide (CO₃) and Its Implications for Atmospheric Chemistry". ChemPhysChem. 7 (12): 2508–2513. doi:10.1002/cphc.200600390. PMID 17029325.

Further reading

• 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. S2CID 120356317.
• 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. S2CID 98748631.
• 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.