Poly[bis­(μ-2-amino-4-nitro­benzoato)di-μ-aqua-dirubidium]

In the structure of the title salt, [Rb(2)(C(7)H(5)N(2)O(4))(2)(H(2)O)(2)](n), the asymmetric unit comprises two independent and different seven-coordinate Rb(+) cations, one forming an RbO(7) polyhedron, the other a RbO(6)N polyhedron, each of which is considerably distorted. The RbO(7) polyhedron comprises bridging O-atom donors from two water mol­ecules, three carboxyl­ate groups, and two nitro groups. The RbO(6)N polyhedron comprises the two bridging water mol­ecules, one monodentate amine N-atom donor, one carboxyl O-atom donor and three O-atom donors from nitro groups (one from the chelate bridge). The extension of the dinuclear unit gives a three-dimensional polymeric structure which is stabilized by both intra- and inter­molecular amine N—H⋯O and water O—H⋯O hydrogen bonds to carboxyl and water O-atom acceptors, as well as a number of inter-ring π–π inter­actions [minimum centroid–centroid separation = 3.364 (2) Å]. The title salt is isostructural with the analogous caesium salt.