Pierre and Marie Curie, c. 1904
23 June 2023
Curium is transuranic, highly radioactive, hard, dense metal with atomic number 96 and the symbol Cm. It is a synthetic element, first produced in 1944 by Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso. Wartime secrecy, however, delayed the announcement of the discovery until 1945, and the name was not proposed until the following year. It is named for chemists Marie and Pierre Curie.
Because it is so highly radioactive, curium has limited uses. It is used in the synthesis of other transuranic elements; in thermoelectric generators, primarily in spacecraft; and in alpha-particle X-ray spectrometers, again, primarily in spacecraft designed to land on Mars and other celestial bodies.
Seaborg proposed the name in a paper given at an American Chemical Society conference on 10 April 1946. The paper was published in Chemical and Engineering News a month later:
For element 96, containing seven 5f electrons, we suggest “curium”, symbol Cm after Pierre and Marie Curie, historical leading investigators in the field of radioactivity; this is by analogy with gadolinium, containing seven 4f electrons, which recalls Gadolin, the great investigator of rare earths.
The Associated Press reported on the naming on 10 April, and the journal Science followed on 19 April 1946.
Sources:
Associated Press. “World A-Energy Controls Declared Necessary: Scientist Says Alternative is Non-Commercial Use of Power.” Columbus Evening Dispatch (Ohio), 10 April 1946, 2-A. Readex: America’s Historical Newspapers.
Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements—Part 3—Rivalry of Scientists in the Twentieth and Twenty-First Centuries.” Foundations of Chemistry, 12 November 2022.
Oxford English Dictionary, second edition, 1989, s.v. curium, n.
Seaborg, Glenn T. “The Impact of Nuclear Chemistry” (10 April 1946). Chemical and Engineering News, 24.9, 10 May 1946, 1192–98 at 1197. DOI: 10.1021/cen-v024n009.p1192.
“U.S. News and Notes.” Science, 103.2677, 19 April 1946, 480–82 at 481. DOI: 10.1126/science.103.2677.480.
Image credit: Unknown photographer, c. 1904. Wikimedia Commons. Public domain image.