3-nitrophthalic acid: C(4) and R(2)(2)(8) motifs of O-H...O hydrogen bonds generate sheets which are linked by C-H...O hydrogen bonds.

In molecules of 3-nitrophthalic acid, C(8)H(5)NO(6), the 2-carboxyl group, which is the central of the three substituents, is almost orthogonal to the arene ring, while the other two substituents are effectively coplanar with the ring. The molecules are linked by two O-H...O hydrogen bonds [H...O = 1.86 and 1.89 A, O...O = 2.6983 (13) and 2.6809 (12) A, and O-H...O = 172 and 155 degrees ] into sheets containing alternating R(2)(2)(8) and R(6)(6)(36) rings; these sheets are linked into a three-dimensional framework by a single C-H.O hydrogen bond [H...O = 2.41 A, C.O = 3.2663 (15) A and C-H...O = 150 degrees ].