Gilbert Newton Lewis (25.10.1875-23.03.1946) was an American physical chemist and a member of the National Academy of Sciences. He was born in Weymouth. He graduated from Harvard University (1896). In 1899-1906 he worked at Harvard University and in 1907—12 at the Massachusetts Institute of Technology. From 1912 he was professor at the University of California at Berkeley.
His main work was in the field of chemical thermodynamics, the chemistry of isotopes, nuclear physics and photochemistry. He proposed a new formulation of the third law of thermodynamics. He developed methods of calculating the free energies of chemical reactions, and proposed and developed (1912—16) the electron theory of the chemical bond, being the first to explain the homopolar and the ionic bond. In 1933, with R. Macdonald, he was the first to obtain heavy water and to isolate deuterium from it. In 1929 he introduced the term “photon”.
He created a school of physical chemists. A foreign member of the USSR Academy of Sciences (1942).