ABSTRACT
Boron chemistry has contributed to the development of bonding theories and concepts due to its unique covalent bonding. Covalently bound trivalent boron chemistry is quite well known, however. Boron has largely been understood by analogy to silicon, but boron has its own unique chemistry, as does any other first-row element. A series of investigations made by A. E. Stockand his co-workers on boron hydrides has opened a whole new area. Boron in its higher oxidation states is quite common, but crystalline boron is chemically also very stable. Owing both to the definite nonpolarity of the bonds and to the electron deficiency of the atoms, no oxidation numbers are assigned to boron in the boranes. The boron carbides are semiconductors, while the nitrides are electrical insulators. The only known chemistry of scandium (Sc) has to do with the Sc(III) oxidation state.
