4-Nitro-2-(1H-tetrazol-1-yl)phenol.

There are two symmetry-independent molecules in the unit cell of the title compound, C(7)H(5)N(5)O(3). The tetrazole and phenyl rings are essentially planar and are not coplanar in either molecule [dihedral angles 30.2 (1) and 7.0 (1) degrees]. In the structure, four molecules are connected by O-H...N bridges, forming four-membered molecular aggregates which are linked together by a complex three-dimensional hydrogen-bond network.