2-Amino-5-chloropyridine–fumaric acid (1/2)

The asymmetric unit of the title compound, C5H5ClN2·0.5C4H4O4, comprises a neutral 2-amino-5-chloropyridine molecule and one half of a fumaric acid molecule which lies on an inversion center. The dihedral angle between the pyridine ring and the plane formed by the fumaric acid molecule is 3.22 (8)°. The 2-amino-5-chloropyridine molecule is planar, with a maximum deviation of 0.004 (1) Å for the pyridine N atom. In the crystal, the 2-amino-5-chloropyridine molecules interact with the carboxyl groups of fumaric acid molecules through N—H⋯O and O—H⋯N hydrogen bonds, forming centrosymmetric R 2 2(8) ring motifs and another N—H⋯O hydrogen bond links these motifs into a two-dimensional network parallel to (100).