A second monoclinic polymorph of 2-amino-4,6-dichloro­pyrimidine

The title chloro-substituted 2-amino­pyrimidine, C4H3Cl2N3, is a second monoclinic polymorph of this compound which crystallizes in the space group C2/c. The structure was previously reported [Clews & Cochran (1948). Acta Cryst. 1, 4–11] in the space group P21/a. There are two crystallographically independent mol­ecules in the asymmetric unit and each mol­ecule is planar. The dihedral angle between the two pyrimidine rings is 30.71 (12)°. In the crystal structure, mol­ecules are linked via N—H⋯N inter­molecular hydrogen bonds, forming infinite one-dimensional chains along the a axis. These hydrogen bonds generate R22(8) ring motifs. The chains are stacked along the b axis.