Synchrotron study of poly[[di-μ-aqua­(μ-2,2′-bipyridyl-5,5′-dicarboxyl­ato)di­potassium] dihydrate]

The title compound, {[K(2)(C(12)H(6)N(2)O(4))(H(2)O)(2)]·2H(2)O}(n), forms a three-dimensional coordination polymer in the solid state. The asymmetric unit consists of one K(+) ion, half of a 2,2′-bipyridyl-5,5′-dicarboxyl­ate ligand, one coordinated water mol­ecule and one solvent water mol­ecule. The K(+) ion is 7-coordinated by the oxygen atoms of two water mol­ecules and by five oxygen atoms of four carboxyl­ate groups, one of which is chelating. The extended structure can be described as a binodal network in which each K(+) is a six-connected node, bonding to four carboxyl­ate groups and two bridging water mol­ecules, and the 2,2′-bipyridyl-5,5′-dicarboxyl­ate linkers are eight-connected nodes, with each carboxyl­ate group bridging four metal centers. Overall, this arrangement generates a complex network with point symbol {3(4).4(12).5(12)}{3(4).4(4).5(4).6(3)}(2). Both of the bridging water mol­ecules participate as donors in hydrogen-bonding inter­actions; one to solvent water mol­ecules and a second to an oxygen atom of a carboxyl­ate group.