STRUCTURE OF BIS(ETHYLENEDIAMINE)COPPER(II) TETRACYANONICKELATE(II)

[Cu(C4H16N4)][Ni(CN)4], M(r) = 346.5, triclinic, P1BAR, a = 6.460 (9), b = 7.230 (10), c = 7.864 (15) angstrom, alpha = 106.81 (13), beta = 91.51 (14), gamma = 106.94 (12)-degrees, V = 333.9 (9) angstrom 3, Z = 1, D(m) = 1.71 (1), D(x) = 1.723 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 3.55 mm-1, F(000) = 177, T = 293 K, final R = 0.056 for 1212 unique observed reflections. The structure consists of centrosymmetric [Cu(en)2]2+ (en = ethylenediamine) cations and [Ni(CN)4]2- anions linked together by two of the CN groups (the remaining two act as unidentate ligands) to form infinite chains running along the [111] direction. Bridging by the CN groups is clearly unsymmetrical [Ni-C = 1.850 (4) and Cu-N = 2.533 (4) angstrom], leading to four-coordinate Ni(II) species alternating with axially distorted octahedral Cu(II) groups along the chain [the equatorial Cu-N distances are 1.997 (3) and 2.001 (3) angstrom].