Tetra-ethyl-ammonium (2,2′-bipyridine)tetra-cyanidocobaltate(III) sesquihydrate acetonitrile solvate

The title complex, (C₈H₂₀N)[Co(CN)₄(C ₁₀H₈N₂)]·CH₃CN·1. 5H₂O, consists of tetra-ethyl ammonium cations, mononuclear [Co ^IIIbpy(CN)₄]^- anions and uncoordinated water and acetonitrile mol-ecules. The Co^III atom is six-coordinated by two 2,2′-bipyridine (bpy) N atoms and four cyanide C atoms in a distorted octa-hedral geometry. The acute bite angle of the chelating bpy [82.28 (8)°] is the main factor accounting for this distortion. In addition, the tetra-ethyl-ammonium cation is significantly disordered [occupancy ratio 0.611 (3):0.389 (3)]. The presence of water mol-ecules, one of which is disordered over two positions about an inversion center, results in the formation of a network of O - H⋯N hydrogen bonds involving the cyanide N atoms.