Carbon tetroxide

"CO4" redirects here. For the Colchester postal district, see CO postcode area.

Carbon tetroxide or Oxygen carbonate (in its C_2v isomer) is a highly unstable oxide of carbon with formula CO
₄. It was proposed as an intermediate in the O-atom exchange between carbon dioxide (CO
₂) and oxygen (O
₂) at high temperatures.^[1] The C_2v isomer, which is 138 kJ mol⁻¹ more stable than the D_2d isomer, was first detected in electron-irradiated ices of carbon dioxide via infrared spectroscopy.^[2]

The D_2d isomer of carbon tetroxide

Carbon tetroxide

Names
IUPAC name C2v isomer: 1,2,3-Trioxetan-4-one Oxygen carbonate Monooxygen carbonate D2d isomer: Carbon diperoxide
Other names C2v isomer: 4-Trioxetanone Trioxetan-4-one D2d isomer: 1,2,4,5-Tetraoxaspiro[2.2]pentane
Identifiers
CAS Number	853179-44-9 Y
3D model (JSmol)	Interactive image
PubChem CID	22321311
CompTox Dashboard (EPA)	DTXSID901028836
InChI InChI=1S/CO4/c2-1-3-5-4-1 Key: ITOJEBDYSWRTML-UHFFFAOYSA-N
SMILES O=C1OOO1
Properties
Chemical formula	CO4
Molar mass	76.007 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

The isovalent carbon tetrasulfide CS₄ is also known from inert gas matrix. It has D_2d symmetry with the same atomic arrangement as CO₄ (D_2d).^[3]