Pseudo-merohedrally twinned tetrakis(1H-imidazole-kappaN3)bis(N-nitrocyanamidato-kappaN)copper(II).

Crystals of the title complex, [Cu(CN3O2)2(C3H4N2)4], the structure of which has been determined by single-crystal X-ray diffraction at 304 K, appear to be pseudo-merohedrally twinned. Transformation to a monoclinic C-centred cell was necessary in order to derive the twin law. Twin refinement in a triclinic unit cell significantly reduced the R value. The asymmetric unit of the triclinic cell consists of one molecule in a general position and two half entities with the Cu atom on a centre of inversion. The coordination of the Cu atom is quasi-octahedral, with four imidazole N-atom donors in the equatorial plane and two cyano N atoms from the N-nitrocyanamidate anion in axial positions. Owing to symmetry in the centrosymmetric molecules, the trans imidazole ligands are parallel, while those in the non-centrosymmetric molecule make angles of 22.8 (2) and 77.9 (2) degrees .