In organic chemistry, a<unk>  group is a functional group composed of a carbon atom double-bonded to an oxygen atom : C=O.
The term<unk>  can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal<unk> , e.g. nickel<unk> ; in this situation, carbon is triple-bonded to oxygen : C≡O.
The remainder of this article concerns itself with the organic chemistry definition of<unk> .
Carbonyl
Carbide
Acyl
Acetyl
Hydrocarbon
Oxamyl
Coenzyme
Amino acid