The three-dimensional coordination polymer tetraethylammonium (ethylenediamine)cadmium(II) hexacyanoferrate(III), (Et(4)N)[[Cd(en)](4)[Fe(CN)(6)](3)].

The title compound, tetraethylammonium dodeca-mu-cyano-hexacyanotetrakis(ethylenediamine)tetracadmium(II)triferrate(III), (C(8)H(20)N)[Cd(4)Fe(3)(CN)(18)(C(2)H(8)N(2))(4)], was prepared from a reaction mixture containing CdCl(2), K(3)[Fe(CN)(6)], ethylenediamine (en) and [Et(4)N]Br in a 1:1:3:1 molar ratio. The crystal structure consists of a negatively charged three-dimensional framework of [[Cd(en)](4)[Fe(CN)(6)](3]n)(n-) anions, with [Et(4)N](+) cations located in the cavities of the framework. The Cd atom is octahedrally coordinated by one disordered chelating en molecule [mean Cd-N = 2.35 (3) A] and four N-bonded bridging cyano groups [Cd-N distances are in the range 2.283 (2)-2.441 (2) A]. There are two crystallographically independent [Fe(CN)(6)](3-) anions in the structure and in each the Fe atom lies on a twofold axis. In the first [mean Fe-C = 1.941 (5) A], all the cyano groups are bridging ligands, while in the second [mean Fe-C = 1.945 (2) A], there are two terminal cyano ligands in trans positions. The Cd-N-C angles range from 128.6 (2) to 172.8 (2) degrees.