August 1939 photo of the 60-inch (152 cm) cyclotron at the University of California, Berkeley used to synthesize californium and other transuranic elements.
28 April 2023
Element 98 is dubbed californium, with the symbol Cf. It was first synthesized in 1950 by a team at the then University of California Radiation Laboratory in Berkeley (now the Lawrence Berkeley National Laboratory). Californium is one of the few transuranic elements with practical applications, used as a source of neutrons in nuclear power plants and in nuclear diffraction and spectroscopy. It is named for both the University of California and for the state.
The discoverers explain their choice of name in a 15 March 1950 letter in the May 1950 issue of the journal Physical Review that officially announced their discovery:
It is suggested that element 98 be given the name californium (symbol Cf) after the university and state where the work was done. This name, chosen for the reason given, does not reflect the observed chemical homology of element 98 to dysprosium (No. 66) as the names americium (No. 95), curium (No.96), and berkelium (No. 97) signify that these elements are the chemical homologs of europium (No. 63), gadolinium (No. 64), and terbium (No. 65), respectively; the best we can do is point out, in recognition of the fact that dysprosium is named on the basis of a Greek word meaning “difficult to get at,” that the searchers for another element a century ago found it difficult to get to California.
But that wasn’t the first instance of the name appearing in print. Word of the discovery had gotten out prior to the official announcement, and the name was revealed in the 25 March 1950 issue of the Science News Letter:
Creation of the 98th and heaviest chemical element through atomic bombardment in the University of California 60-inch cyclotron has been made known.
It has been christened californium, honoring the university and state where the six heaviest trans-uranium elements, including plutonium, have been manufactured and discovered in the past decade.
Sources:
“Californium Element 98.” Science News Letter, 57.12, 25 March 1950, 182. JSTOR.
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 (online).
Oxford English Dictionary, second edition, 1989, s.v. californium, n.
Thompson, S.G., K. Street, Jr., A. Ghiorso, and G.T. Seaborg. “Element 98” (15 March 1950). Physical Review, 78, May 1950, 298.
Photo credit: Unknown photographer, 1939. US National Archives, NAID: 558594. Public domain image.