Acetylacetone is an organic compound with the chemical formula CH3C(=O)CH2C(=O)CH3. It is classified as a 1,3-diketone. It exists in equilibrium with a tautomer CH3C(=O)CH=C(OH)CH3. The mixture is a colorless liquid. These tautomers interconvert so rapidly under most conditions that they are treated as a single compound in most applications.[2] Acetylacetone is a building block for the synthesis of many coordination complexes as well as heterocyclic compounds.