Poly[(aqua-calcium)-μ(4)-pyrazine-2,3-di-carboxyl-ato].

The polymeric title compound, [Ca(C(6)H(2)N(2)O(4))(H(2)O)](n), was synthesized from pyrazine-2,3-dicarb-oxy-lic acid and calcium dichloride under hydro-thermal conditions. The Ca(2+) cation is seven-coordinated by five O atoms and one N atom of four pyrazine-2,3-dicarboxyl-ate anions, and one water mol-ecule. The complete deprotonated pyrazine-2,3-dicarboxyl-ate anion adopts a μ(4)-coordination mode, resulting in the formation of a three-dimensional structure.