Crystal structure of a second monoclinic polymorph of 3-meth­oxy­benzoic acid with Z′ = 1

A new polymorphic form of the title compound, C(8)H(8)O(3), is described in the centrosymmetric monoclinic space group P2(1)/c with Z′ = 1 as compared to the first polymorph, which crystallizes with two conformers (Z′ = 2) in the asymmetric unit in the same space group. In the crystal of the second polymorph, inversion dimers linked by O—H⋯O hydrogen bonds occur and these are linked into zigzag chains, propagating along the b-axis direction by C—H⋯O links. The crystal structure also features a weak π–π inter­action, with a centroid-to-centroid distance of 3.8018 (6) Å. The second polymorph of the title compound is less stable than the reported first polymorph, as indicated by its smaller calculated lattice energy.