Bis(9-amino-acridinium) bis-(pyridine-2,6-dicarboxyl-ato)zincate(II) trihydrate.

In the title compound, (C(13)H(11)N(2))(2)[Zn(C(7)H(3)NO(4))(2)]·3H(2)O, the Zn(II) ion is six-coordinated with the N(4)O(2) donor set being a distorted octa-hedron through two almost perpendicular (r.m.s. deviation of ligand atoms from the mean plane is 0.057†à ) tridentate pyridine-2,6-dicarboxyl-ate ligands [dihedral angle between the ligands = 86.06†(4)°]. The charge is compensated by two 9-amino-acridinium cations protonated on the ring N atom. A variety of inter-molecular contacts, such as ion-ion, N-H⋯O and O-H⋯O hydrogen bonds, and π-π stacking [centroid-centroid distances = 3.4907†(9)-4.1128†(8)†à ], between cations and between anions, play important roles in the formation of the three-dimensional network.