chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, the cyclooctatetraenide anion or cyclooctatetraenide, more precisely cyclooctatetraenediide, is an

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

species with a formula of ₈H₈sup>2− and abbreviated as COT²⁻. It is the di

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

cyclooctatetraene 1,3,5,7-Cyclooctatetraene (COT) is an unsaturated derivative of cyclooctane, with the formula C8H8. It is also known as nnulene. This polyunsaturated hydrocarbon is a colorless to light yellow flammable liquid at room temperature. Because of ...

. Salts of the cyclooctatetraenide anion can be stable, e.g.,

Dipotassium cyclooctatetraenide Dipotassium cyclooctatetraenide, sometimes abbreviated K2COT, is an Organopotassium chemistry, organopotassium compound with the formula K2C8H8. It is a brown solid that is used as a precursor to cyclooctatetraenide complexes, such as uranocene ( ...

or disodium cyclooctatetraenide. More complex

coordination compound A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...

s are known as cyclooctatetraenide complexes, such as the

actinocene Actinocenes are a family of organoactinide compounds consisting of metallocenes containing elements from the actinide series. They typically have a sandwich structure with two dianionic cyclooctatetraenyl ligands (COT2-, which is ) bound to an ...

s. The structure is a planar symmetric

octagon In geometry, an octagon (from the Greek ὀκτάγωνον ''oktágōnon'', "eight angles") is an eight-sided polygon or 8-gon. A '' regular octagon'' has Schläfli symbol and can also be constructed as a quasiregular truncated square, t, whi ...

stabilized by

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillatin ...

, meaning each atom bears a charge of −. The length of the bond between carbon atoms is 1.432 Å. There are 10 π electrons. The structure can serve as a

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...

with various

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

List of salts

References

{{Reflist Simple aromatic rings Anions Non-benzenoid aromatic carbocycles

List of salts

See also

References