Poly[nickel(II)-di-mu-4,4'-bipyridyl-kappa4N:N'-mu-dichromato-kappa2O:O'] and poly[copper(II)-di-mu-4,4'-bipyridyl-kappa4N:N'-mu-dichromato-kappa2O:O'].

The novel title hybrid isomorphous organic-inorganic mixed-metal dichromates, [Ni(Cr2O7)(C10H8N2)2] and [Cu(Cr2O7)(C10H8N2)2], have been synthesized. A non-centrosymmetric three-dimensional (4,6)-net is formed from a linear chain of vertex-linked [Cr2O7]2- and [MN4O2]2+ (M = Ni and Cu) units, which in turn are linked by the planar bidentate 4,4'-bipyridine ligand through the four remaining vertices of the [MN4O2]2+ octahedra. There are two such three-dimensional nets that interpenetrate with inversion symmetry.