Structure and Bonding of Group 14 Clusters: Wade’s Rules and Beyond

Abstract

Clusters of group 14 elements show plenty of similarities with borane clusters. As such, chemists often try to understand their structure and bonding on the basis of Wade’s rules to predict and classify various clusters. Such practice, albeit very common, often faces challenges and difficulties due to significant differences in the bonding abilities between group 13 and 14 atoms, as well as the changes in the ionization energies and radial characteristics of atomic orbitals as the groups are descended. In this chapter, we have extensively discussed the structure and bonding of a wide variety of group 14 clusters, including bare clusters, substituent-decorated clusters, endohedral clusters, transition metal doped clusters, and their combinations. By thoroughly analyzing their electronic structures within the framework of molecular orbital theory, we have summarized their bonding patterns and explored the factors that affect the applicability of Wade’s rules in various group 14 clusters.