4-Hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde)

Molecules of syring­aldehyde, C9H10O4, are connected by intermolecular O—H⋯O [H⋯O = 2.05 Å and O⋯O = 2.713 (2) Å] hydrogen bonds between the 4-hydroxy and 1-aldehyde functions into infinite linear chains. The 4-hydroxy H atoms also participate in an intramolecular O—H⋯O [H⋯O = 2.22 Å and O⋯O = 2.662 (2) Å] interaction with a neighbouring methoxy O atom.