Accurate intensity integration in the twinned γ-form of o-nitro­aniline

o-Nitro­aniline, C6H6N2O3, is known to be polymorphic. The α-form is probably amorphous, while the β- and γ-forms are crystalline. Difficulties with the unit-cell determination of the γ-form were reported as a consequence of twinning. In this paper, newly recorded diffraction data of the γ-form of o-nitro­aniline are described that were processed taking into account the two twin lattices. Data were partly deconvoluted and much better agreement was obtained in terms of R1 values and C—C bond precision. The availability of raw data and proper reprocessing using twin lattices is by far superior to efforts to de-twin processed structure factors.