2-Hy­droxy-3-meth­oxy­benzaldehyde (o-vanillin) revisited

The structure of ortho-vanillin, C(8)H(8)O(3), has been revisited with modern methods and at low temperature (100 K). The previous structure [Iwasaki et al. (1976 ▶). Acta Cryst. B32, 1264–1266] is confirmed, but geometric precision is improved by an order of magnitude. The C atom of the meth­oxy group lies close to the benzene ring plane, which is the most common geometry for –OMe groups lying ortho to –OH groups on an aromatic ring. The crystal structure displays one intra­molecular O—H⋯O and three weak inter­molecular C—H⋯O hydrogen bonds.