A novel double-chain silver(I) coordination polymer: catena-poly[[[μ-aqua-aqua­disilver(I)]-bis­(μ3-5-methyl­pyrazine-2-carboxyl­ato)] dihydrate]

In the title silver(I) coordination polymer, {[Ag(2)(C(6)H(5)N(2)O(2))(2)(H(2)O)(2)]·2H(2)O}(n), the [Ag(2)(μ(2)-H(2)O)(H(2)O)] cores are extended by anti-parallel 5-methyl-pyrazine-2-carboxyl-ate (L) ligands, forming a novel double-chain structure. Both Ag(+) cations show a distorted square-pyramidal coordination. Ag1 is bonded to two water molecules, one L N atom, one N atom and one carboxylate O atom from a neighbouring L, whereas Ag2 is surrounded by two L N atoms, two L carboxylate O atoms and one bridging water molecule. O-H⋯O hydrogen-bonding inter-actions involving water clusters and carboxyl-ate O atoms link the mol-ecules into a three-dimensional supra-molecular architecture, which is further consolidated by weak C-H⋯O inter-actions and π-π stacking inter-actions [centroid-centroid distance 3.643 (5) Å].