einsteinium / fermium

Black-and-white photos of two men in suits: Albert Einstein sitting at desk with an open journal in front of him and Enrico Fermi standing in front of a piece of equipment

Albert Einstein, c. 1920 (left) and Enrico Fermi, 1940s (right)

28 July 2023

Einsteinium, element 99, and Fermium, element 100, were first identified in December 1952 by Albert Ghiorso and others at the University of California, Berkeley and the Argonne and Los Alamos National Laboratories. They found both elements in the fallout from the Ivy Mike nuclear bomb test of November 1952 on Enewetak Atoll, the first test of a hydrogen bomb. Because of its association with nuclear testing the existence of the elements was classified and not announced until 1955.

The elements are, of course, named for physicists Albert Einstein and Enrico Fermi. Ghiorso, et al. wrote of the discovery in the 1 August 1955 issue of Physical Review:

We suggest for the element with the atomic number 99 the name einsteinium (symbol E) after Albert Einstein, and for the element with atomic number 100 the name fermium (symbol Fm), after Enrico Fermi.

The chemical symbol for einsteinium is Es, not E as originally suggested.

Neither element has any practical use other than scientific research.

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Sources:

Ghiorso, A., et al. “New Elements Einsteinium and Fermium, Atomic Numbers 99 and 100.” Physical Review, 99.3, 1 August 1955, 1048–49.

Ghiorso, Albert, “Einsteinium and Fermium,” Chemical and Engineering News, 2003.

Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements—Part 3—Rivalry of the Scientists in the Twentieth and Twenty-First Centuries,” Foundations of Chemistry, 12 November 2022. DOI: 10.1007/s10698-022-09452-9.

Oxford English Dictionary, second edition, 1989, s.v. einsteinium, n., fermium, n.

Photo credits: Einstein: unknown photographer, c. 1920, Wikimedia Commons; Fermi: U.S. Department of Energy, unknown photographer, 1943–49, Wikimedia Commons. Both photos are in the public domain.