Gilbert Newton Lewis (1875-1946) was an American physical chemist whose concept of electron pairs led to modern theories of chemical bonding. His concept of acids and bases was another fundamental contribution.

Gilbert N. Lewis was born at Weymouth, Mass., on Oct. 23, 1875. He received his bachelor's degree in 1896 and his doctorate in 1899 from Harvard University and then served as instructor in chemistry at Harvard until 1900. After a year in Leipzig, Germany, he was in charge of the laboratories of the U.S. Bureau of Weights and Measures in the Philippine Islands in 1904-1905. He became assistant professor of physiochemical research at the Massachusetts Institute of Technology in 1907 and full professor in 1911. He married Mary H. Sheldon in 1912, and they had three children. Also in 1912 he accepted the chairmanship of a small chemistry department at the University of California at Berkeley, where he remained until his death.

In 1916 Lewis published his famous paper "The Atom and the Molecule," in which he proposed that nonionic molecular compounds were the result of the sharing of electrons among atoms. He suggested that a chemical bond was produced in the formation of a molecular compound. This involved the sharing of a pair of electrons by two atoms. He called this a covalent bond, and it became the basis of the electronic theory of the chemical bond.

Lewis made another important scientific observation in 1916, when he propounded the electron-pair concept of acids and bases, in which acids were classified more generally as electron-pair acceptors, and bases as electron-pair donors. This theory was useful in explaining many reactions otherwise difficult to classify. According to this theory, not only proton-donating compounds are classified as acids. Any compound or ion capable of accepting a pair of electrons to form a new compound is considered to be an acid. In 1923 he published Valence and the Structure of Atoms and Molecules. Three years later he wrote The Anatomy of Science.

At Berkeley, Lewis gradually built one of the most powerful and creative chemistry departments in the world. His lectures in thermodynamics drew students from all over the world, many of whom became famous. Among these were Linus Pauling, Harold Urey, Melvin Calvin, and William Giauque, each of whom received the Nobel Prize in chemistry. Many scientists believe that Lewis, who received a large number of science's most prestigious honors, should have become a Nobel laureate in chemistry, but this prize eluded him. He died on March 23, 1946.

Further Reading

• A good account of Lewis and his work is in Great American Scientists, by the editors of Fortune (1961). His major contributions to chemistry are explained on a simple level in Gregory R. Choppin and Bernard Jaffe, Chemistry: Science of Matter, Energy and Change (1965).
• Lachman, Arthur, Borderland of the unknown; the life story of Gilbert Newton Lewis, one of the world's great scientist, New York: Pageant Press, 1955.