Hexaoxotricyclobutabenzene is an organic compound with formula C12O6. It can be viewed as the sixfold ketone of tricyclobutabenzene.

It is an oxide of carbon, detected by 13C NMR in 2006.[1][2]

Structural formula of hexaoxotricyclobutabenzene
Ball and stick model of hexaoxotricyclobutabenzene
IUPAC name
Systematic IUPAC name
3D model (JSmol)
Molar mass 240.12 g mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).


  1. ^ Hamura, T.; Ibusuki, Y.; Uekusa, H.; Matsumoto, T.; Siegel, J. S.; Baldridge, K. K.; Suzuki, K. (2006). "Dodecamethoxy- and Hexaoxotricyclobutabenzene: Synthesis and Characterization". Journal of the American Chemical Society. 128 (31): 10032–10033. doi:10.1021/ja064063e. PMID 16881630.
  2. ^ Butenschön, H. (2007). "A new oxocarbon C12O6 via highly strained benzyne intermediates". Angewandte Chemie. 46 (22): 4012–4014. doi:10.1002/anie.200700926. PMID 17508349.

An oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen.The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide (CO2) with IUPAC names carbon(II) oxide and carbon(IV) oxide respectively. Many other stable (practically if not thermodynamically) or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide (C3O2 or O=C=C=C=O) and mellitic anhydride (C12O9).

While textbooks will often list only the first three, and rarely the fourth, a large number of other oxides are known today, most of them synthesized since the 1960s. Some of these new oxides are stable at room temperature. Some are metastable or stable only at very low temperatures, but decompose to simpler oxocarbons when warmed. Many are inherently unstable and can be observed only momentarily as intermediates in chemical reactions or are so reactive that they can exist only in the gas phase or under matrix isolation conditions.

The inventory of oxocarbons appears to be steadily growing. The existence of graphene oxide and of other stable polymeric carbon oxides with unbounded molecular structures suggests that many more remain to be discovered.


Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often displaying unusual conformations and because of their unusual reactivity. Tricyclobutabenzenes are isomers of radialenes and form an equilibrium with them.

The parent tricyclobutabenzene (C12H12) was first synthesised in 1979 by the following sequence: This compound is stable up to 250 °C (482 °F).

A polyoxygenated tricyclobutabenzene with an extraordinary bond length of 160 pm for the bond connecting two carbonyl groups[1] by the following sequence:

An ordinary bond of this type is only 148 pm and for comparison the C-C bond in isatin is 154 pm long. On the other hand, no change is recorded in the aromatic bond length alternation.

Similar chemistry yielded the six-fold ketone hexaoxotricyclobutabenzene C12O6, which happens to be a novel oxide of carbon. A key starting material is the iodo triflate depicted below which is a benzotriyne synthon.

Common oxides
Exotic oxides
Compounds derived from oxides


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