Poly[[hepta-μ2-aqua-bis­(μ2-pyrazine-2-carboxyl­ato)dibarium] bis­(pyrazine-2-carboxyl­ate)]

In the layered title coordination polymer, {[Ba2(C5H3N2O2)2(H2O)7](C5H3N2O2)2}n, the coordination geometries around the two independent BaII ions can be described as bicapped square-anti­prismatic [BaNO9] arrangements. A two-dimensional polymeric framework with (6,3) topology can be observed in the ac plane, the nodes being provided by BaII 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.