5-Methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylic acid.

The title compound, C(10)H(9)N(3)O(2), was synthesized from azido-benzene and ethyl acetyl-acetate. A pair of hydrogen bonds [2.617 (2) Å] inter-connects a pair of the carboxyl groups, forming an R(2) (2)(8) inversion dimer, a frequent motif in carboxylic acids. In the title structure, the bonding H atom in the aforementioned O-H⋯O hydrogen bond is significantly shifted towards the acceptor O atom [the donor and acceptor O-H distances are 1.25 (4) and 1.38 (4) Å, respectively]. A plot of the O⋯O versus O-H distances in compounds with paired carboxyl groups shows that the title structure belongs to the group of structures with abnormally long O-H distances with regard to the O⋯O contacts. The displacement of the bonding H atom towards the centre of the hydrogen bond is concomitant with more equal C-O bonding distances in the carboxyl group.