Born Apr. 29, 1893, in Walkerton, Ind.; died Jan. 5, 1981, in La Jolla, Calif. American chemist. Member of the National Academy of Sciences.

Urey graduated from the University of Montana with a degree in zoology and taught there from 1919 to 1921. He performed research under G. N. Lewis at the University of California from 1921 to 1924 and then under N. Bohr in Copenhagen. Together with the American chemists F. G. Brickwedde and G. M. Murphy, he discovered deuterium; a report on the discovery was published in 1932.

Beginning in 1940, Urey directed research on the separation of uranium isotopes and the production of heavy water. In 1945 he began studying problems of geochemistry and cosmochemistry. His most important contribution to these fields was the discovery that amino acids are formed upon passage of an electric discharge through a mixture of ammonia, methane, water, and hydrogen; this fact indicates that amino acids may have been formed in the atmosphere.

Urey received a Nobel Prize in 1934.