Gilbert Newton Lewis (1875 - 1946), was the first American physical chemist to produce a pure sample of deuterium oxide (heavy water) in 1933. Heavy water is used in certain types of nuclear reactors where it acts as a neutron moderator to slow down neutrons so they can react with the uranium. Lewis also published several influential works on chemical bonding, the magnetic properties of solutions of oxygen in liquid nitrogen, electron pair theory, and chemical thermodynamics. He coined the term "photon" for the smallest unit of radiant energy in 1926. In 1913, Lewis was elected to the National Academy of Sciences, but resigned in 1934 over a dispute of the institution's internal politics.
- Chemical Heritage Foundation. Gilbert Newton Lewis and Irving Langmuir.
- Woodrow Wilson National Fellowship Foundation. Gilbert Newton Lewis: American Chemist (1875-1946).