"Imagination and shrewd guesswork are powerful instruments for acquiring scientific knowledge . . . " 1. H. van't Hoff The last decades have witnessed a rapid growth of quantum chemistry and a tremendous increase in the number of very accurate ab initio calculations of the electronic structure of molecules yielding results of admirable accuracy. This dramatic progress has opened a new stage in the quantum mechanical description of matter at the molecular level. In the first place, highly accurate results provide severe tests of the quantum mecha nics. Secondly, modern quantitative computational ab initio methods can be synergetically combined with various experimen tal techniques thus enabling precise numerical characterization of molecular properties better than ever anticipated earlier. However, the role of theory is not exhausted in disclosing the fundamental laws of Nature and production of ever increasing sets of data of high accuracy. It has to provide additionally a means of systematization, recognition of regularities, and ratio nalization of the myriads of established facts avoiding in this way complete chaos. Additional problems are represented by molecular wavefunctions provided by the modern high-level computational quantum chemistry methods. They involve, in principle, all the information on molecular system, but they are so immensely complex that can not be immediately understood in simple and physically meaningful terms. Both of these aspects, categorization and interpretation, call for conceptual models which should be preferably pictorial, transparent, intuitively appealing and well-founded, being sometimes useful for semi quantitative purposes."

Organometallic chemistry is a well established research area at the interface of organic and inorganic chemistry. In recent years this field has undergone a ren aissance as our understanding of organometallic structure, properties and mechanism has opened the way for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as medicine, biology, materials and polymer sciences and organic synthesis. For example, in the de velopment of new catalytic processes, organometallic chemistry is helping meet the challenge to society that the economic and environmental necessities of the future pose. As this field becomes increasingly interdisciplinary, we recognize the need for critical overviews of new developments that are of broad significance. This is our goal in starting this new series Topics in Organometallic Chemistry. The scope of coverage includes a broad range of topics of pure and applied or ganometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. Topics in Organometallic Chemistry differs from existing review series in that each volume is thematic, giving an overview of an area that has reached a stage of maturity such that coverage in a single review article is no longer possible. Furthermore, the treatment addresses a broad audience of researchers, who are not specialists in the field, starting at the graduate student level. Discussion of possible future research directions in the areas covered by the individual volumes is welcome."

Metal-ligand interactions are currently being studied in different fields, from a variety of points of view, and recent progress has been substantial. Whole new classes of compounds and reactions have been found; an arsenal of physical methods has been developed; mechanistic detail can be ascertained to an increasingly minute degree; and the theory is being developed to handle systems of ever-growing complexity. As usual, such multidisciplinarity leads to great opportunities, coupled with great problems of communication between specialists. It is in its promotion of interactions across these fields that Metal-Ligand Interactions: From Atoms, to Clusters, to Surfaces makes its timely contribution: the tools, both theoretical and experimental, are highly developed, and fundamental questions remain unanswered. The most fundamental of these concerns the nature of the microscopic interactions between metal atoms (clusters, surfaces) and ligands (atoms, molecules, absorbates, reagents, products) and the changes in these interactions during physical and chemical transformation. In Metal-Ligand Interactions, leading experts discuss the following, vital aspects: ab initio theory, semi-empirical theory, density functional theory, complexes and clusters, surfaces, and catalysis.

The book highlights some of the important present day roles played by Main Group Elements as well as their emergent new roles in the fields of materials science, chemical synthesis and structure, and biological-cum-environmental aspects. Rarely can one find a single book on Main Group elements that comprehensively discusses their impact on fundamental and applied sciences with a multidisciplinary flavour, while catering for the special interests of a wide cross-section of readers.

The second edition of this textbook is identical with its fourth German edi tion and it thus has the same goals: precise definition of basic phenomena, a broad survey of the whole field, integrated representation of chemistry, physics, and technology, and a balanced treatment of facts and comprehen sion. The book thus intends to bridge the gap between the often oversimpli fied introductory textbooks and the highly specialized texts and monographs that cover only parts of macromolecular science. The text intends to survey the whole field of macromolecular science. Its organization results from the following considerations. The chemical structure of macromolecular compounds should be inde pendent of the method of synthesis, at least in the ideal case. Part I is thus concerned with the chemical and physical structure of polymers. Properties depend on structure. Solution properties are thus discussed in Part II, solid state properties in Part III. There are other reasons for dis cussing properties before synthesis: For example, it is difficult to understand equilibrium polymerization without knowledge of solution thermodynamics, the gel effect without knowledge of the glass transition temperature, etc. Part IV treats the principles of macromolecular syntheses and reactions.

S.C. Singhal and X.-D. Zhou: Solid Oxide Fuel Cells.- H. Wang and H.D. Abruna/: Electrocatalysis of Direct Alcohol Fuel Cells: Quantitative DEMS Studies.- J. Benziger, A. Bocarsly, M.J. Cheah, P.Majsztrik, B. Satterfield and Q. Zhao: Mechanical and Transport Properties of Nafion: Effects of Temperature and Water Activity.- S. Sachdeva, J. A. Turner, J.L. Horana and A. M. Herring: The Use of Heteropoly Acids in Proton Exchange Fuel Cells.- M. T. Kelly: Perspective on the Storage of Hydrogen: Past and Future.-"

Ion-exchange Technology II: Applications presents an overview of the numerous industrial applications of ion-exchange materials. In particular, this volume focuses on the use of ion-exchange materials in various fields including chemical and biochemical separations, water purification, biomedical science, toxic metal recovery and concentration, waste water treatment, catalysis, alcohol beverage, sugar and milk technologies, pharmaceuticals industry and metallurgical industries. This title is a highly valuable source not only to postgraduate students and researchers but also to industrial R&D specialists in chemistry, chemical, and biochemical technology as well as to engineers and industrialists.

Ion-exchange Technology I: Theory and Materials describes the theoretical principles of ion-exchange processes. More specifically, this volume focuses on the synthesis, characterization, and modelling of ion-exchange materials and their associated kinetics and equilibria. This title is a highly valuable source not only to postgraduate students and researchers but also to industrial R&D specialists in chemistry, chemical, and biochemical technology as well as to engineers and industrialists.

It is presently well recognized that total concentrations of trace elements in any environmental compartment supply insufficient information to understand important phenomena. The distinction and separate analysis of specific chemical species are essential for understanding cycles in the aquatic environment, involving identification and quantification of sources, transport pathways, distributions and sinks, or, in the area of interactions between trace elements and organisms to understand uptake, distribution, excretion mechanisms and effects. In the past, various ways have been developed to determine the nature and extent of complexation of trace elements in natural systems. Approaches have been followed along very different lines. These have not always been fully appreciated by specialists working in even related fields of complexation research. The first International Symposium on the Complexation of Trace metals in Natural Waters was held at the Netherlands Institute for Sea Research (NIOZ, Texel, the Netherlands from 2-6 May 1983. The scientific programme was planned by the chief organizers Drs. C.J.M. Kramer and J.C. Duinker (NIOZ) together with Prof. Dr. H.W. Nurnberg (Kernforschungsanlage, Julich, Federal Republic of Germany) and Dr. M. Branica (Rudjer Boskovic Institute, Zagreb, Yugoslavia).

1. R.C. Mehrotra, Jaipur, India Present Status and Future Potential of the Sol-Gel Process 2. J. Fricke, A. Emmerling, Wuerzburg, FRG Aerogels - Preparation, Properties, Applications 3. S. Sakka, T. Yoko, Kyoto, Japan Sol-Gel-Derived Coating Films and Applications 4. H. Schmidt, Saarbruecken, FRG Thin Films, the Chemical Processing up to Gelation 5. M. Henry, J.P. Jolivet, J. Livage, Paris, France Aqueous Chemistry of Metal Cations: Hydrolysis, Condensation and Complexation 6. R. Reisfeld, Jerusalem, Israel, C.K. Joergensen, Geneva, Switzerland Optical Properties of Colorants or Luminescent Species in Sol-Gel Glasses

Organolithium chemistry occupies a central position in the selective construction of C-C bonds in both simple and complex molecules. Paralleling the surge of interest in methods for asymmetric synthesis, the use of organolithiums in enantioselective synthesis has witnessed spectacular advances in a little over a decade. This volume is the first dedicated to a comprehensive coverage of this important area. It is designed to provide graduate students and researchers with a rich source of essential information on synthesising molecules in an enantioselective manner using organolithiums, and be an inspiration for future developments. Following an overview chapter summarising the key milestones, successive chapters, each written by leading experts in their field, critically survey all the major areas of progress.

Two decades have passed since the original discovery of recoilless nuclear gamma resonance by Rudolf Mossbauer; the spectroscopic method based on this resonance effect - referred to as Mossbauer spectroscopy - has developed into a powerful tool in solid-state research. The users are chemists, physicists, biologists, geologists, and scientists from other disciplines, and the spectrum of problems amenable to this method has become extraordinarily broad. In the present volume we have confined ourselves to applications of Mossbauer spectroscopy to the area of transition elements. We hope that the book will be useful not only to non-Mossbauer special ists with problem-Oriented activities in the chemistry and physics of transition elements, but also to those actively working in the field of Mossbauer spectroscopy on systems (compounds as well as alloys) of transition elements. The first five chapters are directed to introducing the reader who is not familiar with the technique to the principles of the recoilless nuclear resonance effect, the hyperfme interactions between nuclei and electronic properties such as electric and magnetic fields, some essential aspects about measurements, and the evaluation of Moss bauer spectra. Chapter 6 deals with the interpretation of Mossbauer parameters of iron compounds. Here we have placed emphasis on the information about the electronic structure, in correlation with quantum chemical methods, because of its importance for chemical bonding and magnetic properties."