The composition and structure of the nitrosyl halides of copper (II)

Abstract

The metallic nitrosyls include all those compounds in which the NO group is bonded to a metal atom. Most of the metals capable of complex formation give derivatives of this class. These nitrosyls, which may contain from one to four NO groups to each metal atoms, differ widely in type. Apparently, the NO group can replace almost any other in a complex and can form part of an anion, a cation, or a neutral molecule. In addition, pure metal-nitrosyls and nitrosyl compounds of metal salts, are known. One of the most interesting series is that of the metal-nitrosyl halides. Among these the iron, cobalt and nickel members have been most closely investigated, although it has long been known that solutions of copper (II) sulphate in concentrated sulphuric acid and of copper (II) bromide and chloride in certain organic solvents, notably ethanol and acetone, give rise to intense blue or violet colourations on treatment with nitric oxide. It was in the hope of obtaining some precise information about the composition and structure of these copper (II) nitrosyl halides that the present work was undertaken.