Gilbert N. Lewis

Gilbert Newton Lewis (October 23, 1875 - March 23, 1946) was a famous American physical chemist known for his 1902 Lewis dot structures, his paper "The Atom and the Molecule", which is the foundation of modern valence bond theory, developed in coordination with Irving Langmuir, and his 1923 textbook Thermodynamics and the Free Energy of Chemical Substances, written in coordination with Merle Randall, one of the founding books in chemical thermodynamics. In 1926, Lewis coined the term "photon" for the smallest unit of radiant energy. He was a brother of Alpha Chi Sigma, the professional chemistry fraternity.

Career
After earning his Ph.D., he stayed as an instructor for a year before taking a traveling fellowship, studying under the physical chemist Wilhelm Ostwald at Leipzig and Walther Nernst at Göttingen. He then returned to Harvard as an instructor for three more years, and in 1904 left to become superintendent of weights and measures for the Bureau of Science of the Philippine Islands in Manila. The next year he returned to Cambridge when the Massachusetts Institute of Technology (MIT) appointed him to a faculty position, in which he had a chance to join a group of outstanding physical chemists under the direction of Arthur Amos Noyes. He quickly rose in rank, becoming assistant professor in 1907, associate professor on 1908, and full professor in 1911. He left MIT to become professor of physical chemistry and dean of the College of Chemistry at the University of California, Berkeley in 1912. Lewis Hall at Berkeley, built in 1948, is named in his honor.

Timeline
In 1908 he published the first of several papers on relativity, in which he derived the mass-energy relationship in a different way from Albert Einstein's derivation. He also introduced the thermodynamic concept of fugacity in a paper, "The osmotic pressure of concentrated solutions, and the laws of the perfect solution," ''J. Am. Chem. Soc.'' 30, 668-683 (1908).

On June 21, 1912, he married Mary Hinckley Sheldon, daughter of a Harvard professor of Romance languages. They had two sons, both of whom became chemistry professors, and a daughter.

In 1913, he was elected to the National Academy of Sciences, but in 1934 he resigned in a dispute over the internal politics of that institution.

In 1916, he formulated the idea that a covalent bond consisted of a shared pair of electrons and defined the term odd molecule when an electron is not shared. His ideas on chemical bonding were expanded upon by Irving Langmuir and became the inspiration for the studies on the nature of the chemical bond by Linus Pauling. This year he published what became known as the Lewis structure and the Cubical atom model.

In 1919, by studying the magnetic properties of solutions of oxygen in liquid nitrogen, he found that O4 molecules were formed. This was the first evidence for tetratomic oxygen.

In 1923, he formulated the electron-pair theory of acid-base reactions. In the so-called Lewis theory of acids and bases, a "Lewis acid" is an electron-pair acceptor and a "Lewis base" is an electron-pair donor. This year he also published his book Valence and the structure of atoms and molecules.

Based on work by J. Willard Gibbs, it was known that chemical reactions proceeded to an equilibrium determined by the free energy of the substances taking part. Lewis spent 25 years determining free energies of various substances. In 1923 he and Merle Randall published the results of this study, which helped formalize modern chemical thermodynamics.

In 1926, he coined the term "photon" for the smallest unit of radiant energy.

Lewis was the first to produce a pure sample of deuterium oxide (heavy water) in 1933. By accelerating deuterons (deuterium nuclei) in Ernest O. Lawrence's cyclotron, he was able to study many of the properties of atomic nuclei. During the 1930s, he was faculty advisor and mentor to Glenn T. Seaborg, who was retained for post-doctoral work as Lewis' personal research assistant. Seaborg went on to win the 1951 Nobel Prize in Chemistry and have the element Seaborgium named in his honor while he was still alive.

Later years
In the last years of his life, he established that phosphorescence of organic molecules involves an excited triplet state (a state in which electrons that would normally be paired with opposite spins are instead excited to have their spin vectors in the same direction) and measured the magnetic properties of this triplet state.

During his career he published on many other subjects besides those mentioned in this article, ranging from the nature of light quanta to the economics of price stabilization.

He died at age 70 of a heart attack while working in his laboratory in Berkeley. He had been working on an experiment with liquid hydrogen cyanide, and deadly fumes from a broken line were leaking into the laboratory when a graduate student found the professor's lifeless body under a workbench. The coroner said Gilbert N. Lewis died of coronary artery disease; however, some believe that the death may have been a suicide. UC Berkeley Professor Emeritus William Jolly, who reported the various views on Gilbert N. Lewis' death in his 1987 history of the University of California, Berkeley’s College of Chemistry, From Retorts to Lasers, said one higher-up in the department believed the suicide theory.

A possible explanation for the suicide theories was depression following a lunch with Irving Langmuir. On the day of Gilbert N. Lewis' death, Irving Langmuir and Gilbert N. Lewis met for lunch at the University of California, Berkeley. It was reported by associates that Gilbert N. Lewis came back from the meeting in a dark mood. He reportedly sat down for a morose game of bridge with some colleagues, and then went back to work in his lab. An hour later, Gilbert N. Lewis was dead. Irving Langmuir's papers at the Library of Congress confirm that Irving Langmuir was on the University of California, Berkeley campus that day. Irving Langmuir had gone to the University of California, Berkeley to receive an honorary degree.