Ab initio embedded cluster UMP2 calculations are performed on paramagnetic 3d(9) cis-[Ni(CN)(4)Cl-2](5-) cluster in KCl host lattice taking into account short and long-range crystal interactions. The results confirm the d(x)(2)-(2)(y) unpaired electron orbital assignment, with a small participation of p(x) and p(y) basis functions. Hyperfine interactions are shown to arise mainly from spin polarization of their valence orbitals caused by the unpaired electron. The calculated difference between the two possible Ni-CN distances is 0.25 Angstrom. Chlorine ions, first neighbors to the central metallic atom, as well as the two cyanides pointing to the d(x)(2)-(2)(y) orbital, are found to be not coordinated to the metal. The coordination complex present in the cis-[Ni(CN)(4)Cl-2](5-) cluster is thus assigned to linear [Ni(CN)(2)](-) instead of hexacoordinated or planar forms.