2-Amino-4-nitrophenol monohydrate

The title compound, C6H6N2O3·H2O, crystallizes with two formula units in the asymmetric unit. The molecules are essentially planar with the nitro groups twisted slightly out of the ring planes [maximum deviations from the ring plane of 0.13 (2) and 0.22 (2) Å in the two molecules]. The respective O—N—C—C torsion angles are 6.0 (4) and 12.5 (4)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O, C—H⋯O, O—H⋯O and O—H⋯N interactions into a three-dimensional network.

The title compound, C 6 H 6 N 2 O 3 ÁH 2 O, crystallizes with two formula units in the asymmetric unit. The molecules are essentially planar with the nitro groups twisted slightly out of the ring planes [maximum deviations from the ring plane of 0.13 (2) and 0.22 (2) Å in the two molecules]. The respective O-N-C-C torsion angles are 6.0 (4) and 12.5 (4) . In the crystal structure, molecules are linked by intermolecular N-HÁ Á ÁO, C-HÁ Á ÁO, O-HÁ Á ÁO and O-HÁ Á ÁN interactions into a three-dimensional network.

Related literature
For the use of nitroaromatics as intermediates in explosives, dyestuffs, pesticides and organic synthesis, see: Yan et al. (2006). For the occurrence of nitroaromatics in industrial wastes and as direct pollutants in the environment, see: Yan et al. (2006); Soojhawon et al. (2005). For related structures, see: Tanak et al. (2010); Bi et al. (2009); Garden et al. (2004).
thesis (Yan et al., 2006). Nitroaromatics occur as industrial wastes and direct pollutants in the environment, and are relatively soluble in water and detectable in rivers, ponds and soil (Yan et al., 2006;Soojhawon et al., 2005).
There is two independent molecules in the asymmetric unit of the title compound (I, Fig. 1). The bond lengths and angles in (I) have normal values, and are comparable with those in the related structures (Tanak et al., 2010;Bi et al., 2009;Garden et al., 2004). The aromatic ring systems are almost planar with the maximum deviation, 0.13 (2) Å for atom O1 in the ring system C1-C6 and -0.22 (2) Å for atom O4 in the ring system C7-C12.
In the crystal structure, the molecules are linked by intermolecular N-H···O, C-H···O, O-H···O and O-H···N interactions (see Table I) into a three-dimensional network.

Experimental
The commercially available compound (Acros organics) was recrystallized from ethanol.