The ability to synthesize defined molecular clusters of main group metals and nonmetals has greatly spurred development in cluster science. Clusters of main group elements such as boron, gallium and silicon exhibit unique chemical and physical properties which make them attractive as building blocks for functional materials and for use in high-performance applications. With more than 20 contributions from leading research groups, this book provides essential information for chemists and materials scientists working with molecular clusters. Its systematic coverage of all relevant main group elements makes this the prime reference source in the field. It treats both homonuclear and heteronuclear clusters, including: the theory and concepts in main-group cluster chemistry, novel boranes and heteroboranes, silicon/germanium/tin clusters, alkali metal suboxides, clusters in alloys with mercury, chalkogen clusters and numerous other compound classes. The whole is illustrated by examples of the great potenti al for technical application s such as electron storage, cancer therapy and in materials synthesis. Its systematic coverage of all relevant main group elements makes this the prime reference source in the field.