The triel elements are those of group 13 of the periodic table, including boron. Compounds of boron and other triel centres have been the subject of numerous studies for a long time, with their properties well-known and frequently discussed. However, the more detailed characteristics of triel compounds have not been well analyzed in existing research and their molecular and electronic structures have often been the subject of dispute and controversy. Triel bonds as a thematic area have garnered significant interest in recent years and this book provides a much broader description and explanation of their properties and characteristics than has previously been available, discussing aspects which are unique to triel bonds such as the differences between boron and the heavier triel atoms. The book features four main sections, looking at the theoretical foundations, then the types of interactions, before moving onto the main section demonstrating key examples of triel bonds as well as their characteristics. The concluding section then provides illustrative examples of triel elements functioning as catalysts and boron compounds in hydrogen storage. Theoretical and Physical Chemistry of Triel Bonding: Properties, Mechanisms, and Catalysis is written primarily for advanced undergraduate and graduate students and researchers in physical or theoretical/computational chemistry who may be working on intermolecular interactions and in the field of catalysis. It is also likely to be of interest to organic and inorganic chemists and relevant to those in molecular engineering, nanotechnology, and molecular biology.