Hannah

Tautomers of Acetylacetone (C₅H₈O₂)

Usually the keto tautomer is favored

Keto = ketone

Enol = alcohol

may also be referred to as an alkenol

Keto Acetylacetone

With geometry optimization

But PubChem's 3D structure has both oxygens pointing in the same direction

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But NIST has the oxygens pointing different directions

Proton NMR (Hartree-Fock)

Enol Acetylacetone

Proton NMR (Hartree-Fock)

A reminder of Proton NMR stretches: File:nmr1.gif