Date Published: May 01, 2009
Publisher: International Union of Crystallography
Author(s): Gustavo Portalone.
The crystal structure of the title compound, C7H5NO4, was first reported by Kurahashi, Fukuyo & Shimada [(1967). Bull. Chem. Soc. Jpn, 40, 1296]. It has been re-examined, improving the precision of the derived geometric parameters. The asymmetric unit comprises a non-planar independent molecule, as the nitro and the carboxy substituents force each other to be twisted away from the plane of the aromatic ring by 54.9 (2) and 24.0 (2)°, respectively. The molecules form a conventional dimeric unit via centrosymmetric intermolecular hydrogen bonds.
For the previous structure determination, see: Kurahashi et al. (1967 ▶); Sakore et al. (1967 ▶); Tavale & Pant (1973 ▶). For the effect of nitro and carboxy substitution on the geometry of polysubstituted benzene rings, see: Colapietro et al. (1984 ▶); Domenicano et al. (1989 ▶). For the formation of hydrogen-bonded dimers in monocarboylic acids, see:Leiserowitz (1976 ▶). For computation of ring patterns formed by hydrogen bonds in crystal structures, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶); Motherwell et al. (1999 ▶).