Two polymorphs of N-phenylpyridin-4-amine

The title compound, N-phenylpyridin-4-amine, forms two polymorphs I and II which were obtained from acetonitrile or tetrahydrofuran, respectively. The molecular structures in both polymorphs are similar one another. The pyridyl rings show better conjugation with the lone pairs of the nitrogen atom than phenyl rings. In both polymorphs, the molecules also form a similar sheet structure in which they make zigzag hydrogen bonds. Judged by powder XRD analysis, polymorph I was considered to be the most stable phase at room temperature.