No abstract

No abstract

FOR many years workers in the field of co-ordination chemistry were concerned almost exclusively with the stereochemistry of complexes and with the preparation of complexes of new types or containing new ligands (or co-ordinating groups). The nature of the forces involved between the metal ion and the co-ordinating atom was also a problem which attracted a number of workers, and the present situation has been reviewed by Nyho1m.l Until fairly recently the physicochemical principles involved in complex formation had received scant attention, and there was little quantitative information available to show the influence of the ligand on the properties of the complexes formed by a particular metal, or how the properties of complexes containing the same ligand depended on the position of the metal in the Periodic Table . The aim of this Review is to present a concise picture of the present state of our knowledge of these factors and to show the importance of a fuller understanding of them.The properties of the complex compounds of a metal are not usually regarded as being typical of the metal in the same way as are those of the insoluble compounds and simple salts. This is probably due to the influence of the ligand on the properties of complexes. I n aqueous solution, however, metal ions are invariably hydrated, and in many cases it is to be supposed that water molecules are co-ordinated to the ion to give aquo-complexes analogous to the ammines and other typical co-ordination compounds. I n a number of cases, involving the metals whose salts are hydrolysed in solution, hydroxo-complexes, where OHgroups are coordinated, or possibly even 0x0-complexes, containing 0-ions, may be formed. These usually polymerise and may finally give colloidal solutions of the metal hydroxide. Anions which are present also co-ordinate, and in acid solutions, where hydrolysis is prevented, considerable numbers of anions may be attached to the metal ions. In the cases of some metals, particularly those of the platinum group, simple solvated ions are never formed, and the chemistry of such metals is essentially the chemistry of their complex compounds.Complex formation affects the properties of the metal ions, often very considerably. I n extreme cases, such as the formation of [Fe(CN),]----

No abstract

Bwkin : CompLexes between Metal Salts aPzd 26. Complexes between Metal Salts and Long-chain Aliphatic Amines.Part I . The Complexes of Cupric Salts with Long-chain Amines.