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Roald Hoffmann
born 1937 · United States, Poland · 20th century
Nobel Chemistry 1981
Co-formulated the Woodward–Hoffmann rules on orbital symmetry in reactions and applied extended Hückel theory to inorganic and solid-state chemistry.
Nobel Prize work
Hoffmann, with Robert Burns Woodward, formulated the rules of conservation of orbital symmetry (1965), which predict the stereochemical course of pericyclic reactions — cycloadditions, electrocyclic reactions, sigmatropic shifts — from the symmetry of frontier orbitals. He later generalized orbital-symmetry arguments to organometallic and inorganic chemistry. The prize, shared with Kenichi Fukui, honored these theories governing the course of chemical reactions.