Poly[diamminedi-μ₃-dicyanamido-copper(II)]

The asymmetric unit of the title polymeric mononuclear Cu^II complex, [Cu(C₂N₃)₂(NH₃)₂]_n, contains one half-mol­ecule, the complex being completed through inversion symmetry, with the Cu^II atom situated on the centre of symmetry. The coordination polyhedron around Cu^II is a Jahn–Teller-distorted [CuN₆] octa­hedron. The terminal N atoms of two dicyanamide ligands and two ammine ligands form an approximate square plane, with N—Cu—N bite angles of 89.72 (5) and 90.28 (5)°. The coordination polyhedron is completed in the axial positions by the central amide-type N atoms of two additional dicyanamide ligands, with an elongated Cu—N distance of 2.548 (1) Å. In turn, each of the four dicyanamide ligands, acting as bidentate, link the Cu^II ions into a two-dimensional polymeric structure parallel to (100). The ammine H atoms are involved in inter­molecular hydrogen bonding with the free terminal N atoms of neighbouring dicyanamide ligands, yielding a three-dimensional network.