catena-Poly[[tetra-aqua-cobalt(II)]-µ-2,2'-dihydroxy-5,5'-diazenediyldibenzoato].

In the title compound, [Co(C(14)H(8)N(2)O(6))(H(2)O)(4)](n), each 5,5'-diazenediylbis(2-hydroxy-benzoato) ligand acts as a dicarboxyl-ate bridge, leading to the formation of polymeric chains running in the [10] direction. The Co atom is hexa-coordinated in a distorted octa-hedral geometry by six O atoms [Co-O = 2.039 (4)-2.115 (4) Å] from two ligands and four water mol-ecules. Inter-molecular O-H⋯O and O-H⋯N hydrogen bonds build up a three-dimensional supra-molecular structure.