[8] Lewis also researched on relativity and quantum physics, and in 1926 he coined the term "photon" for the smallest unit of radiant energy.

[16][17][18][19][20] On March 23, 1946, Lewis was found dead in his Berkeley laboratory where he had been working with hydrogen cyanide; many postulated that the cause of his death was suicide.

After a year of teaching at Phillips Academy in Andover, Lewis returned to Harvard to study with the physical chemist T. W. Richards and obtained his Ph.D. in 1899 with a dissertation on electrochemical potentials.

[21][22] After a year of teaching at Harvard, Lewis took a traveling fellowship to Germany, the center of physical chemistry, and studied with Walther Nernst at Göttingen and with Wilhelm Ostwald at Leipzig.

In the following years, Lewis started to criticize and denounce his former teacher on many occasions, calling Nernst's work on his heat theorem "a regrettable episode in the history of chemistry".

In 1904 Lewis was granted a leave of absence and became Superintendent of Weights and Measures for the Bureau of Science in Manila, Philippines.

[16][19] While at Berkeley he also refused entry to women, including preventing Margaret Melhase from conducting graduate studies.

His decision to resign may also have been sparked by his resentment over the award of the 1934 Nobel Prize for chemistry to his student, Harold Urey, for his 1931 isolation of deuterium and the confirmation of its spectrum.

Lewis had been working on an experiment with liquid hydrogen cyanide, and deadly fumes from a broken line had leaked into the laboratory.

The coroner ruled that the cause of death was coronary artery disease, because of a lack of any signs of cyanosis,[34] but some believe that it may have been a suicide.

Langmuir's papers at the Library of Congress confirm that he had been on the Berkeley campus that day to receive an honorary degree.

Lewis’ early papers also reveal an unusually advanced awareness of J. W. Gibbs's and P. Duhem's ideas of free energy and thermodynamic potential.

Most chemists relied on the familiar thermodynamics of heat (enthalpy) of Berthelot, Ostwald, and Van ’t Hoff, and the calorimetric school.

He derived free energy from fugacity; he tried, without success, to obtain an exact expression for the entropy function, which in 1901 had not been defined at low temperatures.

Although Lewis’ fugacity-based system did not last, his early interest in free energy and entropy proved most fruitful, and much of his career was devoted to making these useful concepts accessible to practical chemists.

At Harvard, Lewis also wrote a theoretical paper on the thermodynamics of blackbody radiation in which he postulated that light has a pressure.

Lewis’ paper remained unpublished; but his interest in radiation and quantum theory, and (later) in relativity, sprang from this early, aborted effort.

About 1902 Lewis started to use unpublished drawings of cubical atoms in his lecture notes, in which the corners of the cube represented possible electron positions.

In 1902, while trying to explain the laws of valence to his students, Lewis conceived the idea that atoms were built up of a concentric series of cubes with electrons at each corner.

[42] 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.

In 1924, by studying the magnetic properties of solutions of oxygen in liquid nitrogen, Lewis found that O4 molecules were formed.

In 1921, Lewis was the first to propose an empirical equation describing the failure of strong electrolytes to obey the law of mass action, a problem that had perplexed physical chemists for twenty years.

Over the course of his career, Lewis published on many other subjects besides those mentioned in this entry, ranging from the nature of light quanta to the economics of price stabilization.