Oxides of Carbon - General Structure

General Structure

Normally carbon is tetravalent while oxygen is divalent, and in most oxocarbons (as in most other carbon compounds) each carbon atom may be bound to four other atoms, while oxygen may be bound to at most two. Moreover, while carbon can connect to other carbons to form arbitrarily large chains or networks, chains of three or more oxygens are rarely if ever observed. Thus the known electrically neutral oxocarbons generally consist of one or more carbon skeletons (including cyclic and aromatic structures) connected and terminated by oxide (-O-, =O) or peroxide (-O-O-) groups.

Carbon atoms with unsatisfied bonds are found in some oxides, such as the diradical C₂O or :C=C=O; but these compounds are generally too reactive to be isolated in bulk. Loss or gain of electrons can result in monovalent negative oxygen (-O−), trivalent positive oxygen (≡O+), or trivalent negative carbon (≡C−). The last two are found in carbon monoxide, −C≡O+. Negative oxygen occurs in most oxocarbon anions.