Cyclooctatetraenide anion

In chemistry, the cyclooctatetraenide anion or cyclooctatetraenide is an aromatic species with a formula of [C₈H₈]²⁻ and abbreviated as COT²⁻. Its name derives from the molecule cyclooctatetraene. Salts of the cyclooctatetraenide anion can be stable, e.g., Dipotassium cyclooctatetraenide or Disodium cyclooctatetraenide. more complex coordination compounds are known as cyclooctatetraenide complexes, such as actinocene

It is a octagonal, planar, cyclic ion; as well, it has 10 π-electrons (4n+2, where n=2), which fulfills Hückel's rule of aromaticity. It can coordinate as a ligand to metal atoms.

The structure shown is a composite of resonance contributors in which each carbon carries part of the negative charge.