Diacridinium trans-diaqua-bis(pyrazine-2,3-dicarboxyl-ato)cobaltate(II) hexa-hydrate.

The title compound, (C(13)H(10)N)(2)[Co(C(6)H(2)N(2)O(4))(2)(H(2)O)(2)]·6H(2)O, consists of mononuclear trans-Co(pz-2,3-dc)(2)(H(2)O)(2) complex anions, (acrH)(+) cations and uncoordinated water mol-ecules (acr is acridine and pz-2,3-dcH(2) is pyrazine-2,3-dicarboxylic acid). The Co(II) atom, which lies on a crystallographic center of symmetry, has a slightly distorted octa-hedral coordination environment, with two N and two O atoms from the (pz-2,3-dc)(2-) ligands in the equatorial plane and with two water mol-ecules in axial positions. In the crystal, the components are held together by two distinct N-H⋯O and C-H⋯O hydrogen bonds with R(2) (2)(8) graph-sets. The coordinated and uncoordinated water mol-ecules are also involved in O-H⋯O hydrogen bonds, which lead to the formation of layers with R(3) (3)(12) graph-set motifs. Extensive π-π stacking inter-actions between parallel aromatic rings of the acridinium ions, with distances ranging from 3.533 (1) to 3.613 (1) Å, occur in the structure.