It is 25 years since the seminal papers describing the relationships between the skeletal geometrics and closed shell electronic requirements of metal clusters were originally published. The electron counting rules which developed from these papers, are now to be found in all undergraduate inorganic textbooks. This volume provides a contemporary account of recent applications of the methodology and the mathematical foundations of the rules. In addition it describes how it is possible to accomondate acception to the rules within a wider framework. The authors are the foremost authorities in the field and give a broad introduction to the area.

Mathematical cluster chemistry.- Metal-metal interactions in transition metal clusters with ?-donor ligands.- Electron count versus structural arrangement in clusters based on a cubic transition metal core with bridging main group elements.- Metallaboranes.- Clusters with interstitial atoms from the p-block: How do Wade's rules handle them?.- Diverse naked clusters of the heavy main-group elements. Electronic regularities and analogies.