A second orthorhombic polymorph of 3,5-diphenyl-4H-1,2,4-triazol-4-amine

The present crystal structure is the second orthorhombic polymorph of the title compound, C14H12N4. Whereas the structure in Pnma with Z′ = 0.5 is already known [Ikemi et al. (2002). Heterocycl. Commun. 8, 439–442], the present structure crystallizes in the space group Pbca with Z′ = 1. The dihedral angle between the two phenyl rings is 23.5 (4)° and the dihedral angles between central ring and the phenyl rings are 41.0 (3) and 26.3 (5)°. In the 4-amino-1,2,4-trizole fragment, the C=N distances are 1.321 (3) and 1.315 (3) Å, which are much shorter than the C—N distances of 1.367 (3) and 1.357 (3) Å. In the crystal, adjacent molecules are linked by N—H...N hydrogen bonds.