Considerable attention has been focussed on non-aqueous chemistry in the last decade and this situation has arisen no doubt from a realization of the vast application of this branch of chemistry. Within this field much energetic work has been channelled into the determination of the coordination chemistry of tran sition metals in these solvent 8ystems. Elaborate experimental techniques have been developed to discover, in particular, the magnetic and spectral properties of complex compounds, and the theoretical background of such systems has been expanded to corroborate, as far as possible, the experimental results. This text has, however, a different bias from many books currently available on this branch of chemistry, and is designed to be a survey of known facts on many of the non-aqueous solvents currently in use mainly in the field of halogen chemistry, together with a discussion of these facts in the light of accepted principles. As such, it is hoped to close a gap in the literature of which many workers and advanced students in this field will be aware. The treatment is meant to be selective rather than completely comprehensive and must unevitably reflect some of the special interests of the author.

Arising no doubt from its pre-eminence as a natural liquid, water has always been considered by chemists as the original solvent in which very varied chemical reactions can take place, both for preparational and for analytical purposes. This explains the very long-standing interest shown in the study of aqueous solutions. In this con nection, it must be stressed that the theory of Arrhenius and Ostwald (1887-1894) on electrolytic dissociation, was originally devised solely for solutions in water and that the first true concept of acidity resulting from this is linked to the use of this solvent. The more recent development of numerous physico-chemical measurement methods has made possible an increase of knowledge in this area up to an extremely advanced degree of systematization. Thus today we have available both a very large amount of experimental data, together with very refined methods of deduction and of quantitative treatment of chemical reactions in solution which enable us to make the fullest use of this data. Nevertheless, . it appears quite evident at present that there are numerous chemical processes which cannot take place in water, and that its use as a solvent imposes 2 INTRODUCTION limitations. In order to overcome these limitations, it was natural that interest should be attracted to solvents other than water and that the new possibilities thus opened up should be explored.

Solvation, Ionic and Complex Formation Reactions in Non-Aqueous Solvents: Experimental Methods for their Investigation presents the available methods and their particular value in investigating solutions composed of non-aqueous solvents. This book is composed of 10 chapters and begins with a brief description of the complexity of the interactions possible n solutions. The subsequent chapters deal with a classification of the solvents and empirical solvent strength scales based on various experimental parameters, together with various correlations empirically describing the solvent effect. Other chapters present the methods for the purification of solvents and ways of checking their purity, as well as the individual results achieved during investigations of the solvent effect, particularly the general regularities recognized. The remaining chapters provide a review of the coordination chemistry of non-aqueous solutions. This book will prove useful to analytical and inorganic chemists.

We believe this to be the first monograph devoted to the physicochemical properties of solutions in organic solvent systems. Although there have 1 been a number of books on the subject of non-aqueous solvents - 4, they have been devoted, almost entirely, to inorganic solvents such as liquid ammonia, liquid sulphur dioxide, etc. A variety of new solvents such as dimethylformamide, dimethylsulphoxide and propylene carbonate have become commercially available over the last twenty years. Solutions in these solvents are of technological interest in connection with novel battery systems and chemical synthesis, while studies of ion solvation and transport properties have fostered academic interest. This monograph is primarily concerned with electrolytic solutions although discussion of non-electrolyte solutions has not been excluded. We have deliberately omitted consideration of the important area of solvent extraction, since this has been adequately covered elsewhere. Our contributors were asked to review and discuss their respective areas with particular reference to differences in technique necessitated by use of non-aqueous solvents while not reiterating facts well-known from experience with aqueous solutions. We have striven to build their contributions into a coherent and consistent whole. We thank our con tributors for following our suggestions so ably and for their forebearance in the face of our editorial impositions.