Crystal structure and infrared spectrum of trans-diaquobis(pyridine-2-carboxamide)copper(II) chloride, [Cu(H2O)2(C5H4N·CO·NH2)2]Cl2

Abstract

The crystal structure of trans-diaquobis(pyridine-2-carboxamide)copper(II) chloride has been determined from three-dimensional X-ray photographic data. The crystals are monoclinic, space group P2₁/c with Z= 2 in a unit cell of dimensions a= 6·32, b= 10·34, c= 14·69 Å and β= 114·9°. The structure is built up of centrosymmetric complex ions and chloride ions. The ligand molecules are co-ordinated through the ring nitrogen and amide oxygen; the chelate ligand is distorted out of the co-ordination plane. The octahedron is completed by two water molecules, bonded at a distance of 2·54 Å. The i.r. spectrum is discussed with respect to the crystal structure, and confirms the existence of extensive hydrogen bonding throughout the unit cell.