Impressionsof the Development of the Open-Shell Chemistryand Multiple Bonding in Heavier Main-Group Species

Several major developments in the synthetic organometallic and inorganic chemistry of molecules featuring multiple bonds between open-shell heavier main-group elements (period 3 or heavier) that coincide with PPP’s independent career are reviewed herein. An emphasis has been placed on the discovery of new classes of molecules and element–element bonds that were not known prior to 1981. The major theoretical work that describes the bonding in these species is also briefly reviewed along with some of the unusual reactivity that is now accessible. It is concluded that these advances have come about mainly as a result of exploratory inorganic and organometallic synthesis.