Tetra-aqua-diazido-cobalt(II) 3,3'-dicarb-oxy-l-ato-1,1'-ethyl-enedipyridinium.

The asymmetric unit of the title compound, [Co(N(3))(2)(H(2)O)(4)]·C(14)H(12)N(2)O(4), comprises half of the cobalt(II) complex mol-ecule and a half of the 3,3'-dicarboxyl-ato-1,1'-ethyl-enedipyridinium mol-ecule. The Co(II) atom is located on an inversion centre and hence the complex mol-ecule adopts a centrosymmetric trans-octa-hedral geometry. The zwitterionic organic mol-ecule is also centrosymmetric with the centre of the C-C bond of the ethyl-ene moiety coinciding with an inversion centre. The adduct of metal complex and organic mol-ecule is associated into a three-dimenional network through O-H⋯O hydrogen bonds.