Maltol Hydrochloride

The unit cell of the title compound, 3-hydroxy-2-methyl-4H-pyran-4-onium chloride, C₆H₇O₃⁺.Cl⁻, contains Cl⁻ anions and carbonyl-protonated maltolium cations, connected into perfectly planar ribbons via hydrogen bonding. The C=O bond length is increased by ca 0.06 Å upon protonation, whereas greater delocalization in the ring π-system makes the double bonds 0.02 Å longer and the single bonds 0.02–0.03 Å shorter than in the neutral molecule.

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