catena-Poly[[[aqua(pyrazine-2-carboxamide-κ2N1,O)zinc]-μ-pyrazine-2-carboxamide-κ3N1,O:N4] dinitrate]

In the crystal of the title compound, {[Zn(C5H5N3O)2(H2O)](NO3)2}n, the ZnII cation is N,O-chelated by two pyrazine-2-carboxamide (PCA) ligands and is further coordinated by one water molecule and by one pyrazine-N atom from an adjacent PCA ligand in a distorted ZnN3O3 octahedral geometry. One of the two independent PCA ligands bridges two ZnII cations, forming a zigzag polymeric chain running along the c axis. In the crystal, the NO3− anions link to the chain via O—H...O and N—H...O hydrogen bonding. Weak intermolecular C—H...O interactions also occur