Tetra-aqua-diazido-cobalt(II) 4,4'-dicarboxyl-ato-1,1'-ethyl-enedi-pyridinium dihydrate.

In the title compound, [Co(N(3))(2)(H(2)O)(4)]·C(14)H(12)N(2)O(4)·2H(2)O, the metal complex mol-ecule is centrosymmetric, the Co(II) ion being six-coordinated by two azide N atoms and four aqua O atoms with a trans-octa-hedral geometry. The zwitterionic organic mol-ecule is also centrosymmetric. In the crystal, the components are associated into a two-dimensional network through O-H⋯O hydrogen bonds. Further O-H⋯O and O-H⋯N inter-actions give a three-dimensional structure. The free water molecule is disordered over two positions in a 0.787 (5):0.213 (5) ratio.