Acetylacetonate, C₅H₇O₂^-, is the conjugate base of 2,4-pentanedione. It is commonly abbreviated acac. This anion forms complexes with many transition metal ions. Some examples include: Mn(acac)₃, VO(acac)₂, Fe(acac)₃, and Co(acac)₃. These compounds are typically soluble in organic solvents. They are widely used as catalyst precursors.