This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). In this project funded by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division, Roald Hoffmann of Cornell University will use theoretical methods to understand structure and bonding in solids under high pressure and the bonding and electronic properties of extended structures of various dimensions. This research has the potential to identify new types of superconductors and to uncover new electronic materials. The PI will also recast the Mott-Jones or Hume-Rothery model for magic electron counts in intermetallic compounds into chemical terms. This work should result in a framework for understanding the properties of solids that is broadly applicable to chemical problems. The PI will also continue to promote science literacy to the general public through a variety of innovative media, including plays, poetry, public speaking, and cabaret acts.