Polymeric hexa-mu-nicotinato-tricadmium(II) tetrahydrate.

The title polymeric complex, poly[tetraaquatricadmium(II)-hexa-mu-nicotinato], [Cd(3)(C(6)H(4)NO(2))(6)(H(2)O)(4)](n), exhibits two types of metal centers, i.e. a seven-coordinated Cd atom and a six-coordinated Cd atom located on an inversion center. The seven-coordinated Cd atoms are linked by kappa(3)N:O,O'-nicotinate bridges into one-dimensional chains that are further linked by kappa(2)N,O-nicotinate-Cd2-kappa(2)N,O-nicotinate bridges into a two-dimensional network which is parallel to the xy plane and which contains large 24- and 36-membered rings.