Abstract: | Studies of the spectra of cyclopolysilanes have led to several significant conclusions. These molecules possess both easily ionized Si-Si bonding electrons and low energy delocalized antibonding orbitals, and can therefore serve either as electron donors or acceptors. This model explains the similarity in properties between cyclopolysilanes and aromatic hydrocarbons. Further investigations of cyclopolysilanes seem likely to provide the key to understanding of controversial questions of bonding in metalloid compounds even as studies of their carbon analogs, the cyclic and cage hydrocarbons, have been crucial to present knowledge of organic stereochemistry and reaction mechanisms. The reactions of cyclopolysilanes are not only interesting in themselves, but have opened the way to the synthesis of complex polysilanes and thus to whole new areas of study. Improved methods of synthesis and isolation are needed, but the number and kinds of compounds that can be prepared seem almost limitless. Perhaps a polymetal chemistry comparable in breadth and variety to carbon chemistry is now developing. |