The nitrides and carbides of boron and silicon are proving to be an excellent choice when selecting materials for the design of devices that are to be employed under particularly demanding environmental and thermal con- tions. The high degree of cross-linking, due to the preferred coordination numbers of the predominantly covalently bonded constituents equalling or exceeding three, lends these non-oxidic ceramics a high kinetic stability, and is regarded as the microscopic origin of their impressive thermal and mechanical durability. Thus it does not come as a surprise that the chemistry, the physical properties and the engineering of the corresponding binary, ternary, and even quaternary compounds have been the subject of intensive and sustained efforts in research and development. In the five reviews presented in the volumes 101 and 102 of "Structure and Bonding" an attempt has been made to cover both the essential and the most recent advances achieved in this particular field of materials research. The scope of the individual contributions is such as to address both graduate students, specializing in ceramic materials, and all scientists in academia or industry dealing with materials research and development. Each review provides, in its introductory part, the chemical, physical and, to some extent, historical background of the respective material, and then focuses on the most relevant and the most recent achievements.

Chemists have been aware of the existence of coordination compounds con taining organic macrocyclic ligands since the first part of this century; however, only during the past few years have they expanded research into the chemistry of these compounds. The expansion was initiated in the early 1960s by the synthesis and characterization of compounds containing some new macrocyclic ligands. The synthesis of compounds which may serve as model systems for some natural products containing large rings as ligands provided the main goal for the early expansion of research effort; indeed, a recurrent theme behind much of the reported chemistry has been the analogy between synthetic macrocyclic compounds and many natural-product systems. More recently, the emphases of reported research have ranged over the whole spectrum of chemistry, and the number of publications that discuss macrocyclic chemistry has increased at a dramatic rate. The completed research has been reported in a variety of journals throughout the world but there has been no previous attempt to bring the major developments together under one cover. This book, therefore, attempts to satisfy the need for a single source in which there is both a collection and a correlation of information concerning the coordination chemistry of macrocyclic compounds. The chapters in this book discuss various aspects of macrocyclic chemistry, and while these chapters as a whole constitute an in-depth survey of the state-of the-art of the field, each chapter is written as a complete unit."

The second volume of the series on inorganic biochemistry and bio physics is singularly devoted to magnetic resonance on systems of high molecular complexity. Recently, there have been important advances in magnetic resonance studies of polymers; these advances touch on all aspects of magnetic resonance, both theoretical and applied. Particular emphasis is placed here on multipulse experiments. We believe such an report will be of considerable interest to the readers of our series owing to the importance of magnetic resonance techniques in the investigation of biopolymers. Ivano Bertini Harry Gray Series Editors Preface This book is a record of the Proceedings of the International Symposium on "Advanced Magnetic Resonance Techniques in Systems of High Molecular Complexity," which was held in Siena between 15 and 18 May 1985. The idea of the meeting is due to Proff. N.M. Atherton, G. Giacometti and E. Tiezzi with the aim of honouring the scientific personality of Prof. S.I. Weissman. The meeting has been organized with the assistance of a National Committee formed by R. Basosi, I. Bertini, P. Bucci, C. Corvaia, A. Gamba, G. Martini, G.F. Pedulli, P.A. Temussi, and C.A. Veracini. The invited lecturers responded enthusiastically and a comprehensive picture of the theoretical and practical aspects of magnetic resonance could be therefore provided. The book contains all the plenary lectures delivered during the meeting and also a wide selection among the huge amount of contributions collected by the organizers."

The papers included in this volume were presented at the symposium on "Americium and Curium Chemistry and Technology" at the International Chemical Congress of Pacific Basin Societies in Honolulu, Hawaii, December 16-21, 1984. This symposium commemorated forty years of research on americium and curium. Accordingly, the papers included in this volume begin with historical perspectives on the discovery of americium and curium and the early characterization of their chemical properties, and then cover a wide range of subjects, such as thermodynamic properties, electronic structure, nuclear reactions, analytic chemistry, high pressure phase transitions, and technological aspects. Thus, this volume is a review of the chemistry of americium and curium, and provides a perspective on the current research on these elements forty years after their discovery. The editors would like to thank the participants in this symposium for their contributions. It is a pleasure to acknowledge the assistance of Ms. Barbara Moriguchi in handling the administrative aspects of the symposium and of the production of this volume. April 2, 1985 Norman M. Edelstein Materials and Molecular Research Division Lawrence Berkeley Laboratory University of California Berkeley, California 94720, U.S.A. James D. Navratil Rockwell International Rocky Flats Plant P.O. Box 464 Golden, Colorado 80402-0464, U.S.A. Wallace W. Schulz Rockwell Hanford P.O. Box 800 Richland, Washington 99352, U.S.A.

The continually growing contribution of transition metal chemistry to synthetic organic chemistry is, of course, widely recognized. Equally well known is the difficulty in keeping up-to-date with the multifarious reactions and procedures that seem to be spawned at an ever-increasing rate. These can certainly be summarized on the basis of reviews under the headings of the individual transition metals. More useful to the bench organic chemist, however, would be the opposite type of concordance based on the structural type of the desired synthetic product. This is the approach taken in the present monograph, which presents for each structural entity a conspectus of the transition metal-mediated processes that can be employed in its production. The resulting comparative survey should be a great help in devising the optimum synthetic approach for a particular goal. It is presented from an essentially practical viewpoint, with detailed direc tions interspersed in the Houben-Weyl style. The wide scope of the volume should certainly encourage synthetic organic chemists to utilize fully the range and versatility of these transition metal-mediated processes. This will certainly be a well-thumbed reference book R. A. RAPHAEL Cambridge University v Preface In recent years an enormous amount of work has been done on the catalysis of organic reactions by various transition metal species and on the organic reactivity of organo-transition-metal compounds."

Research on metal-containing polymers began in the early 1960's when several workers found that vinyl ferrocene and other vinylic transition metal TI -complexes would undergo polymerization under the same conditions as conventional organic monomers to form high polymers which incorporated a potentially reactive metal as an integral part of the polymer structures. Some of these materials could act as semi conductors and possessed one or two dimensional conductivity. Thus applications in electronics could be visualized immediately. Other workers found that reactions used to make simple metal chelates could be used to prepare polymers if the ligands were designed properly. As interest in homogeneous catalysts developed in the late 60's and early 70's, several investigators began binding homogeneous catalysts onto polymers, where the advantage of homogeneous catalysis - known reaction mechanisms and the advantage of heterogeneous catalysis - simplicity and ease of recovery of catalysts could both be obtained. Indeed the polymer matrix itself often enhanced the selectivity of the catalyst. The first symposium on Organometallic Polymers, held at the National Meeting of the American Chemical Society in September 1977, attracted a large number of scientists interested in this field, both established investigators and newcomers. Subsequent symposia in 1977, 1979, 1983, and 1987 have seen the field mature. Hundreds of papers and patents have been published."

The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.

This book presents the lectures and posters of some of the main leaders in the field of th magnesium research and medical applications delivered at the 8 International Symposium on Magnesium, which took place on 5-9 October, 1997 in Heraklion, Crete under the chairmanship of Professor Theophilos Theophanides. The meeting was sponsored by the National Technical University of Athens and Ministry of Industry, Energy and Technology. The aim of this meeting was to promote research and applications of magnesium and interface between medical doctors, clinicians and scientists in order to understand the mechanisms responsible for magnesium involvement in the pathogenesis of diseases, its biological significance, metabolism and many other utilizations which are associated with membranes and cells. The success of this interface is due to the contribution of its participants who came from all continents and to their high scientific level. The topics, which were presented, and the questions, which were asked, concerned mechanisms of mode of action of free magnesium cations, Mg2+, hydrated cations, 2 Mg2+. 6 HP, and magnesium linked cations Mg +.LxH 0, where L: ligand and x = 2 1...6 Hp. We would like to express our utmost gratitude to the sponsers and to extend our deep appreciation and thanks to all those who helped and encouraged the scientific and material organization of this meeting. We wish to thank all the members of the scientific committee and the organizing committee.

The aim of this book is, as its title suggests, to help sOilleone with little or no knowledge of what thermal analysis can do, to find out briefly what the subject is all about, to decide whether it will be of use to him or her, and to help in getting started on the more common techniques. Some of the less-common techniques are mentioned, but more specialized texts should be consulted before venturing into these areas. This book arose out of a set of notes prepared for courses on thermal analysis given at instrument workshops organized by'the S.A. Chemical Institute. It has also been useful for similar short courses given at various universities and technikons. I have made extensive use ofthe manufacturers' literature, and I am grateful to them for this information. A wide variety of applications has been drawn from the literature to use as examples and these are acknowledged in the text. A fuller list of the books, reviews and other literature ofthermal analysis is given towards the back of this book. The ICTA booklet 'For Better Thermal Analysis' is also a valuable source of information. I am particularly grateful to my wife, Cindy, for typing the manuscript, to Mrs Heather Wilson for the line drawings, and to Professor David Dollimore of the University of Toledo, Ohio, for many helpful suggestions.

Walter C. J. ROSS Emeritus Professor, University of London To paraphrase a statement made by Howard E. Skipper many years ago, 'We cancer chemotherapists have often exploited and overworked our chemist colleagues and they have been conveniently forgotten at award giving times'. This book is an attempt to rectify this and highlight the contribution of the chemist in modifying the structure of various types of agent to enhance their effectiveness as inhibitors of the growth of neoplastic tissues. Cancer chemotherapy is a relatively new discipline, coming later than the introduction of sulphonamides and antibiotics. Modern anti-cancer therapy started with the report of the use of a war gas methyl-di-(2-chloroethyl)amine (HN2) in 1946 for the treatment of Hodgkin's disease. The recognition that this compound acted as a bifunctional alkylating agent under physiological conditions led to the synthesis of a wide range of drugs with similar properties. Amongst these were chlorambucil, melphalan, busulphan, and cyclophos phamide which still find use today. Somewhat later, a range of antibiotics was found to be effective, for example aminopterin (1948) and 6-mercaptopurine (1958) to treat acute leukaemias and 5-fluorouracil and 6-azauracil (1957-8) which were used against a variety of cancers. Since these early days the net has been cast ever wider and, as well as ingenious modifications of the compounds mentioned above, anticancer drugs now include growing classes of compounds ranging from purely synthetic agents to natural products. Many of these are discussed in the present book."

Surface organometallic chemistry is a new field bringing together researchers from organometallic, inorganic, and surface chemistry and catalysis. Topics ranging from reaction mechanisms to catalyst preparation are considered from a molecular basis, according to which the "active site" on a catalyst surface has a supra-molecular character. This. the first book on the subject, is the outcome of a NATO Workshop held in Le Rouret. France, in May. 1986. It is our hope that the following chapters and the concluding summary of recommendations for research may help to provide a definition of surface organometallic chemistry. Besides catalysis. the central theme of the Workshop, four main topics are considered: 1) Reactions of organometallics with surfaces of metal oxides, metals. and zeolites; 2) Molecular models of surfaces, metal oxides, and metals; 3) Molecular approaches to the mechanisms of surface reactions; 4) Synthesis and modification of zeolites and related microporous solids. Most surface organometallic chemistry has been carried out on amorphous high-surf ace-area metal oxides such as silica. alumina. magnesia, and titania. The first chapter. contributed by KNOZINGER. gives a short summary of the structure and reactivity of metal oxide surfaces. Most of our understanding of these surfaces is based on acid base and redox chemistry; this chemistry has developed from X-ray and spectroscopic data, and much has been inferred from the structures and reactivities of adsorbed organic probe molecules. There are major opportunities for extending this understanding by use of well-defined (single crystal) oxide surfaces and organometallic probe molecules."

The rate of advance in areas of science is seldom constant. Usually certain fields effloresce with activity because of the ealization that solutions are possible to long standing important problems. So it is now with asymmetric catalysis, a field which promises to change profoundly the strategic thinking of synthetic chemists. As this Report will show, reagents which can induce catalytic enantiocontrol of chemical transformations could represent the ultimate synthetic method. Nearly all synthetic strategies of complex molecules involve steps which require enantiocontrol and, in many cases, a specific catalytic transformation embodying enan tiocontrol has enormous advantages in terms of the rate and economy of the reaction. Because asymmetric catalysis is in a formative stage, workers with different backgrounds have joined the field. This Workshop had representatives with organometallic, organic, structural, kinetic, enzymatic, microbiological and industrial backgrounds. Each had his own perspective and this Report represents a consensus of this group of eleven people. The result is probably as compre hensive and balanced a view of the subject as is possible at present. It is hoped that those who have until now had but a glancing interest in asymmetric catalysis will find this Report a useful indication of its present state. We believe that asymmetric catalysis will have an increasing impact on the development of chemistry and will eventually dominate much of synthetic and industrial chemistry."

The literature contains tens of thousands of publications and patents devoted to the synthesis, characterization and processing of polymers. Despite the fact that there are more than one hundred elements, the majority of these publications and patents concern polymers with carbon backbones. Furthermore, the limited (by comparison) number of publications on polymers that contain elements other than carbon in their backbones are typically devoted to polymers based on silicon, especially those with Si-O bonds. This disparity is partially a consequence of the dearth of low cost organometallic feedstock chemicals potentially useful for polymer synthesis. It also derives from the lack of general synthetic techniques for the preparation of organometallic polymers. That is, by comparison with the numerous synthetic strategies available for the preparation of organic polymers, there are few such strategies available for synthesizing tractable, organometallic polymers. In recent years, commerical and military performance requirements have begun to challenge the performance limits of organic polymers. As such, researchers have turned to organometallic polymers as a possible means of exceeding these limits for a wide range of applications that include: (1) microelectronics processing (e.g. photoresists) [1]; (2) light weight batteries (conductors and semi-conductors) [2]; (3) non-linear optical devices [3] and, (4) high temperature structural materials (e.g. ceramic fiber processing) [4,5].

Biological inorganic chemistry is a field of research at the interface of inorganic and biological chemistry. The rapidly developing insights into the role of metals in biological systems has far-reaching implications not only for biological science but also for related disciplines, ranging from molecular medicine to the environment. In each volume the reader, whether engaged in chemistry, biochemistry, biology or molecular medicine, receives a comprehensive summary and critical overview of a topic of hight current interest written by leading international experts.

Essential themes in the biochemical cycling of mercury are the relative importance of anthropogenic versus natural sources, transformation and migration processes at the local, regional and global scale, global emission inventories of different mercury sources (both point and diffuse) of both natural and anthropogenic origin. In this regard, Siberia, with its vast territory and variety of natural zones, is of special interest in the global mercury cycle and in terms of the influence of geographical zones on source and sink terms in regional budgets. Siberia contains large areas of mercuriferous belts; natural deposits that emit mercury into the atmosphere and water. Siberian gold has been mined with the use of mercury since the early 1800s. But there, too, huge forest zones and vast areas of tundra and wetland (bogs) can act as efficient sinks for atmospheric mercury. Audience: Environmental scientists, legislators, politicians and the interested citizen wishing to gain a clear picture of the biogeochemical cycling of mercury.

This volume contains the papers and reports presented at the First International Conference on Dye-Protein Interaction, held 24-28 July 1988 at the University of Compiegne, France. This was the first international meeting dealing entirely with dye-protein interaction. The major focus of the conference was on the better understanding of the mechanism of interaction of proteins with different triazine dyes and the synthesis of novel structural dyes having good biomimetic activities. The potentials and limits of their use in biotechnology, mainly for purification, were stressed. Current contributions in developing dye-based affinity methods were highlighted in such areas as affinity partition, affinity precipitation and new support matrices for efficient affinity chromatography, etc. The interrelation between metal chelates and dyes in terms of their interactions with proteins was underlined. It is our belief that this proceedings volume will be a stimulus for broad and creative applications of dye affinity concepts in many fields of biomedical research and biotechnology. for understanding the In addition, a discussion session emphasised the necessity toxicological aspects of these dyes, their fragments and their metabolites. This helped to trigger plans for future work, and this topic will be one of the priorities in a future meeting on dye-protein interactions. C. R. The help of the International Scientific Committee, which included Drs Lowe (UK), G. KopperschHiger (GDR) , E. Stellwagen (USA), D. Thomas (France), G. Birkenmeier (GDR), S. Rajgopal-Narayan (USA), J. P. Dandeu (France), D. Muller (France) and E. Dellacherie (France), in organising this meeting is gratefully acknowledged.

Solid-State NMR is a branch of Nuclear Magnetic Resonance which is presently experiencing a phase of strongly increasing popularity. The most striking evidence is the large number of contributions from Solid-State Resonance atNMR meetings, approaching that ofliquid state resonance. Important progress can be observed in three areas: Methodological developments, applications to inorganic matter, and applications to organic matter. These developments are intented to be captured in three volumes in this series, each of them being devoted to more or less one of these areas. The present volume on Solid-State NMR III is devoted mainly to organic matter. The recent developments of deuteron NMR and their applications are reviewed in the first chapter. Crosspolarization, MAS, and dynamic angle spinning are being explored for enhancement of information and sensitivity. In addition to the analysis of classical relaxation times and modern 2D spectra, detailed dynamic information becomes accessible from investigations of the relaxation time anisotropies. The second chapter examines cross-polarization in static and rotating solids under conditions of spin diffusion and thermal motion. The underlying dipole-dipole interaction is further exploited by the techniques described in the third chapter for studies of polymer-polymer miscibility. Short range techniques are discriminated from long-range techniques based on spin diffusion. The use ofthese techniques is illustrated by a case study ofPMMAJPVF blends. The last chapter addresses novel z methods and applications of two-dimensional exchange NMR for investigations of relative molecular orientations, polymer morphology, molecular dynamics, and macroscopic molecular order."

The design, -synthesis, and selective pyrolytic conversion of organo metallic precursdrs to materials of high purity or specific morphology (for electronic or optical applications), high strength and/or high-temperature stability (for structural or refractory applications) represents a poten tial area of extreme growth at the overlap of chemistry and materials science (materials chemistry). Research in this area is likely to have considerable impact at both the academic and societal levels because it will require development of scientific expertise in areas currently not well understood. Examples include: (1) The thermodynamics of molecular rearrangements in organometallic molecules at temperatures above 200 DegreesC; (2) The electronic properties of amorphous ceramic materials; (3) The phys icochemical properties of ceramic molecular composites; and (4) The optical properties of multicomponent glasses made by sol-gel processing. The opportunity to establish the scientific principles needed to pursue useful research goals in "materials chemistry" requires communica tion between chemists, ceramists, metallurgists, and physicists. To date, there have been few opportunities to create an environment where such communication might occur. The objective of this NATO Advanced Research Workshop was to promote discussions between experts in the varibus disci plines aligned with "materials chemistry. " These discussions were intended to identify the scope and potential rewards of research efforts in the development of: Custom-designed precursors to common and exotic materials, methods of selectively transforming these precursors in high yield to the desired material, and methods of characterizing the final products.

The field of low-dimensional conductors has been very active for more than twenty years. It has grown continuously and both the inorganic and organic materials have remark able properties, such as charge and spin density waves and superconductivity. The discovery of superconductivity at high temperature in copper-based quasi two-dimensional conducting oxides nearly ten years ago has further enlarged the field and stimulated new research on inorganic conductors. It was obviously impossible to cover such a broad field in a ten day Institute and it seemed pertinent to concentrate on inorganic conductors, excluding the high Tc superconducting oxides. In this context, it was highly desirable to include both physics and chemistry in the same Institute in order to tighten or in some cases to establish links between physicists and chemists. This Advanced Study Institute is the continuation of a series of similar ones which have taken place every few years since 1974. 73 participants coming from 13 countries have taken part in this School at the beautiful site of the Centre de Physique des Houches in the Mont-Blanc mountain range. The scientific programme included more than forty lectures and seminars, two poster sessions and ten short talks. Several discussion sessions were organized for the evenings, one on New Materials, one on New Topics and one on the special problem of the Fermi and Luttinger liquids. The scientific activity was kept high from the beginning to the end of the Institute."

This, the second and final volume of Reactions of Coordinated Ligands, describes the chemistry of ligands bound through non-carbon atoms, and of coordinated carbon dioxide. As before, emphasis is on the underlying mechanisms, which provide a unity of understanding for superficially disparate processes. The wide range of topics covered illustrates well both the versatility and the usefulness of coordination chemistry in the controlled activation of ligands. Looking to the future, carbon dioxide is the feedstock of last resort. The homogeneous reduction of dinitrogen to ammonia now seems unlikely to replace the Haber process, but solution reactions also lead to more complex, varied, and valuable products. Nitrogen monoxide, a "non innocent" ligand, impinges as pollutant and reagent. Its rich chemistry stems from its linked roles as three-electron donor, and as extremely powerful -acceptor. In the hydrolysis and condensation of complexed amides, esters etc., metals act both as templates and as tunable and poly functional Lewis acids. Here the control of hydrophobic and steric interactions begins to model the subtle mechanisms of biological specificity. Finally, phosphorus and sulfur are imporant both as ligand atoms in themselves, and as anchors for other functionalities. I would like to thank all those who have been involved in the writing and production of this work, and also my colleagues old and new, at Glasgow and the University of North Texas, for their support. Paul S. Braterman v CONTENTS 1. Reactions of Coordinated Carbon Dioxide 1 J. D. Miller 1."

Combined oxygen, in the form of water, metal oxides, silicates and other oxyions, accounts for about 50% by weight of the earth's crust. The chemistry of this most abundant element has two major aspects: that of water and aqueous solutions of electrolytes, and that of the solid state. The methodology and techniques appropriate for the study of these fields are sufficiently different that there have been very few points of contact between solution- and solid state chemists. One such contact, of great potential value, is provided by the extensive class of polyoxoanions formed by the transition metals of groups 5 and 6. As 'heteropoly and isopoly acids' these polyanions have been known and investigated for more than a century. The pre sent book is an attempt to survey the chemistry, structures, and applications of these species. Although the book forms part of a series in inorganic chemistry, the field of polyoxometalates deserves wider attention, for example, from organic chemists, especially those concerned with homogeneous and heterogeneous catalysis, and from biochemists, solid state- and materials scientists."

In this book, originally published in 1983, a synthesis of old and new notions straddling the disciplines of physics and chemistry is described; and this provides a means of exploiting ligan-field properties of transition-metal and lathanide complexes leading to a quantified chemical insight into the individual metal-ligand interactions in these molecular species. Electronic spectroscopy and the ESR technique are well documented, but there has long been a need for a thorough description of magnetochemistry. A major section of this book therefore provides a details account of the physics and chemistry of paramagnetism. The second main section is concerned with those aspects of ligand-field theory that are required to construct the working composite defining ligand-field analysis. Though the book is intended for the research chemist, the subject matter and level of some of the material is suitable for both advanced undergraduate and postgraduate chemists and solid-state physicists.

This volume reports the main lectures and seminars given at the NATO Advanced Study Institute on Vibronic Processes in Inorganic Chemistry held at Riva del Sole, Tuscany, Italy between 7th and 18th September 1988. In addition to the about 40 hours of lectures repres ented by this volume, a further fifteen lectures on current research topics were given by the other participants. Many factors contributed to the decision to hold this ASI but the final trigger was given at a meeeting in Padova when Marco Bettinelli, Lorenzo Disipio and Gianluigi Ingletto asked me to recommend a text where the diverse conceptual, spectroscopic and structural consequences of the impossibility of treating the motions of the electrons and nuclei independantly in inorganic compounds were presented. There seemed to be no suitable comprehensive text where the relationship between the relatively simple theoretical ideas and the huge range of their application in inorganic chemistry and physics was developed. The Institute and this text are a contribution to filling this gap. Seventy-nine participants from fifteen countries attended the Institute. Topics raised in the lectures and from the participants own research frequently led to discussions which went on long into the night."

Molten salts have been used for many years in a large number of industrial applications, and interest in them has increased mark edly in the present century. There is a vast amount of experi mental data published on molten salt systems, and much of this is due to Russian workers. In 1961 the Russian Academy of Sciences published a manual dealing with work in the period 1886-1955. These were updated in 1979 with the publication of a 3-volume collection of binary phase diagrams. The present volume is a translation of the Russian books but is restricted to the systems involving halides. In order to keep the length of the book within bounds the data have been recast. The Russian work treats each system in detail, giving data, methods of study, references, and figures, where available, all together. In this translation all the information is given, but to keep the length down the methods have been classified, the references collected at the end of the volume, and the data given in tabular form. All the figures for halide systems in the Russian volume are included. In the tables, concentrations are given in mole percent; in some cases these have been converted from weight per cent in the original Russian. Where the Russian work was. in tabular form, these have been translated as given. Where the figures exist, these are referred to in the text."

The nitrides and carbides of boron and silicon are proving to be an excellent choice when selecting materials for the design of devices that are to be employed under particularly demanding environmental and thermal con- tions. The high degree of cross-linking, due to the preferred coordination numbers of the predominantly covalently bonded constituents equalling or exceeding three, lends these non-oxidic ceramics a high kinetic stability, and is regarded as the microscopic origin of their impressive thermal and mechanical durability. Thus it does not come as a surprise that the chemistry, the physical properties and the engineering of the corresponding binary, ternary, and even quaternary compounds have been the subject of intensive and sustained efforts in research and development. In the five reviews presented in the volumes 101 and 102 of "Structure and Bonding" an attempt has been made to cover both the essential and the most recent advances achieved in this particular field of materials research. The scope of the individual contributions is such as to address both graduate students, specializing in ceramic materials, and all scientists in academia or industry dealing with materials research and development. Each review provides, in its introductory part, the chemical, physical and, to some extent, historical background of the respective material, and then focuses on the most relevant and the most recent achievements.