Oxides of Carbon - Linear Carbon Dioxides

Linear Carbon Dioxides

One family of carbon oxides has the general formula C_nO₂, or O=(C=)_nO — namely, a linear chain of carbon atoms, capped by oxygen atoms at both ends. The first members are

• CO₂ or O=C=O, the well-known carbon dioxide.
• C₂O₂ or O=C=C=O, the extremely unstable ethylene dione.
• C₃O₂ or O=C=C=C=O, the metastable carbon suboxide or tricarbon dioxide.
• C₄O₂ or O=C=C=C=C=O, tetracarbon dioxide or 1,2,3-Butatriene-1,4-dione
• C₅O₂ or O=C=C=C=C=C=O, pentacarbon dioxide, stable in solution at room temp. and pure up to −90 °C.

Some higher members of this family have been detected in trace amounts in low-pressure gas phase and/or cryogenic matrix experiments, specifically for n = 7 and n = 17, 19, and 21.