Polymeric Carbon Oxides
Carbon suboxide spontaneously polymerizes at room temperature into a carbon-oxygen polymer, with 3:2 carbon:oxygen atomic ratio. The polymer is believed to be a linear chain of fused six-membered lactone rings, with a continuous carbon backbone of alternating single and double bonds. Physical measurements indicate that the mean number of units per molecule is about 5–6, depending on the formation temperature.
| Terminating and repeating units of polymeric C3O2. | |||||||||
| Oligomers of C3O2 with 3 to 6 units. | |||||||||
Carbon monoxide compressed to 5 GPa in a diamond anvil cell yields a somewhat similar reddish polymer with a slightly higher oxygen content, which is metastable at room conditions. It is believed that CO disproportionates in the cell to a mixture of CO2 and C3O2; the latter forms a polymer similar to the one described above (but with a more irregular structure), that traps some of the CO2 in its matrix.
Another carbon-oxygen polymer, with C:O ratio 5:1 or higher, is the classical graphite oxide and its single-sheet version graphene oxide.
Read more about this topic: Oxides Of Carbon