Poly[[hepta-μ(2)-aqua-bis­(μ(2)-pyrazine-2-carboxyl­ato)dibarium] bis­(pyrazine-2-carboxyl­ate)]

In the layered title coordination polymer, {[Ba(2)(C(5)H(3)N(2)O(2))(2)(H(2)O)(7)](C(5)H(3)N(2)O(2))(2)}(n), the coordination geometries around the two independent Ba(II) ions can be described as bicapped square-anti­prismatic [BaNO(9)] arrangements. A two-dimensional polymeric framework with (6,3) topology can be observed in the ac plane, the nodes being provided by Ba(II) ions and the connectors being N and O atoms belonging to pyrazine-2-carboxyl­ate ligands and O atoms of bridging water mol­ecules. Non-coordinating pyrazine-2-carboxyl­ate ions are located between the polymeric layers in the crystal and are interconnected through extensive O—H⋯N,O hydrogen bonding.