Bis(2,2′-bipyridine-κ(2) N,N′)bis­(1H-indole-2-carboxyl­ato-κ(2) O,O′)cadmium–2,2′-bipyridine–water (1/0.5/2)

The asymmetric unit of title compound, [Cd(C(9)H(6)NO(2))(2)(C(10)H(8)N(2))(2)]·0.5C(10)H(8)N(2)·2H(2)O, consists of one complex mol­ecule, one half of an uncoordinated 2,2′-bipyridine mol­ecule and two solvent water mol­ecules. The uncoordinated 2,2′-bipyridine mol­ecule is located on a center of symmetry. Within the complex mol­ecule, the Cd(II) atom is coordinated by four N atoms from two 2,2′-bipyridine ligands and three O atoms from two 1H-indole-2-carboxyl­ate anion ligands, completing a distorted CdN(4)O(3) penta­gonal bipyra­mid. The mol­ecules are assembled into one-dimensional chains along the [100] direction through classical hydrogen bonds (O—H⋯N, N—H⋯O and O—H⋯O). The resulting chains are further connected into two-dimensional supra­molecular layers parallel to the (110) direction by inter­molecular classical hydrogen bonds (N—H⋯O and O—H⋯O) from adjacent chains. A three-dimensional supra­molecular network is formed via interlayer and O—H⋯O hydrogen bonds.