Sodium bis-(ethyl-enedi-amine)-copper(II) tetra-cyanido-cuprate(I)

The title compound, Na[Cu(en)2][Cu(CN)4], where en represents ethyl-enedi-amine, NH2CH2CH2NH2, crystallizes as a salt with two distinct cations, Na(+) and [Cu(II)en2](2+), and discrete [Cu(I)(CN)4](3-) anions. The anion geometry is tetra-hedral, with angles at the copper atom ranging from 105.0 (1) to 115.4 (1)°. The Cu-C distances are in the range 1.976 (3) to 1.993 (3) Å. The divalent copper atom is coordinated by four N atoms of the two bidentate en ligands in a slightly distorted square-planar geometry. In the crystal, each sodium ion inter-acts with cyanide N atoms of four different anions, with Na-N distances lying in the narrow range of 2.344 (3) to 2.367 (3) Å, and an approximately tetra-hedral arrangement around the sodium ions. The inter-acting sodium ions and [Cu(I)(CN)4](3-) anions form a three-dimensional network with channels which contain the [Cu(en)2](2+) cations. One of the chelate rings in the cation shows partial disorder between two different conformations and the C atoms were refined with occupancies in the ratio 0.817 (15):0.183 (15).