born: January 31, 1868, Germantown, Philadelphia, Pennsylvania, United States
died: April 2, 1928, Cambridge, Massachusetts, United States
American chemist whose correct determination of the atomic weights of roughly 25 elements indicated the existence of isotopes and earned him the 1914 Nobel Prize for Chemistry.Richards greatly improved the methodology of gravimetric atomic weight determinations, introducing quartz apparatus, the bottling instrument, and thenephelometer . Even supposing the atomic weight values of Jean Servais Stas had been considered standard, about 1903 physicochemical measurements confirmed that some were not correct. Richards and his college students revised these figures, decreasing, for instance, Stas’s value for silver from 107.93 to 107.88. Richards’ investigations of the atomic weight of lead from completely different sources helped to verify the existence of isotopes. His later researches had been concerned primarily with the physical properties of the stable elements and integrated much authentic work on atomic volumes and compressibilities.
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