in your element Frantically forging fermium Brett F. Thornton and Shawn C. Burdette relate how element 100 was first identified in a nuclear weapons test, but that was classified information, so researchers had to ‘discover’ it again using other methods.

hen the circumstances December, 1952 and the following months”. To surrounding a discovery mean cement their discovery priority, they suggested Wthat its publication is blocked the name fermium in the paper’s title. by external forces, how do you ensure Typically in science, two independent, that you can claim appropriate credit for near-simultaneous discoveries are afforded your findings? This was the case with the recognition. Oxygen was independently discovery of element 100 — fermium — found by Joseph Prisetley in 1774 and which was named for Enrico Fermi who, Carl Wilhelm Scheele around 1773. among many other things, developed the first Lutetium was independently discovered nuclear reactor. Fermium was first produced by Georges Urbain and Carl Auer von in the Ivy Mike thermonuclear weapons test Welsbach in 1907. Nevertheless, the

at Enewetak Atoll in November 1952; this led Stockholm group is rarely, if ever, credited EMMA KARLSSON, SOFIA SWEDEN STOCKHOLM, to a rush to produce the element by different with a shared discovery of element 100. The means in order to circumvent a publication bombarding a uranium target with 16O6+ ions Stockholm experiments reported in embargo on results associated with the tests for several hours4. Due to the numerological 1954 probably represent an independent on that group of islands in the Pacific Ocean. significance, the name centurium for element discovery of element 100: with Cold War Undiscovered heavy transuranium 100 had been circulating in the scientific secrecy, the NI group was unlikely to have isotopes had been postulated as by-products community. NI director Manne Siegbahn known about the UCRL group’s earlier of large nuclear explosions because the wrote to Glenn Seaborg at UCRL to inform discovery before its publication in 1955. high neutron flux might cause uranium him of the discovery and suggested the Element 100 was not the last bit of to undergo multiple neutron captures name nobelium. element-discovery controversy for the NI. almost instantaneously. A research group The UCRL group, realizing they were in a A few years later, they reported the led by Albert Ghiorso at the University of discovery race, had been conducting similar production of element 102, a claim California Radiation Laboratory (UCRL) experiments with oxygen- and nitrogen-ion challenged by both UCRL and a Soviet found element 99 in atmospheric filter beams on uranium and plutonium targets. group. Assigning discovery credit of element samples collected from the Ivy Mike test. After producing253 99, the UCRL team 102 took decades. This time, however, the In larger fallout samples from a nearby coaxed another neutron into the nucleus, name provided for element 102 by the NI atoll they found several other neutron-rich hoping to obtain 25499, which would then group — nobelium — stuck, even though isotopes, including 255100. The formation undergo β-decay to form 254100. Their their discovery claim did not6. ❐ of 255100 was attributed to the β-decay of success was published5 on 1 March 1954 — a 25599, which itself originated from multiple mere ten days after the production of250 100 BRETT F. THORNTON is in the Department β decays of uranium that had absorbed many in Stockholm — in a paper in which they of Geological Sciences and Bolin Centre for neutrons in the explosion to yield 255U. took care to overtly mention the existence of Climate Research, Stockholm University, 255100 eluted from an ion-exchange column earlier “unpublished [classified] information”. 106 91 Stockholm, Sweden. at the expected time1,2; however, the UCRL The NI article would appear just a few e-mail: [email protected] team was barred from reporting a discovery months later, on 15 July4. from the classified weapons test. Ghiorso The earlier classified information — the SHAWN C. BURDETTE is in the knew his team had discovered element production of element 100 in the Ivy Mike Department of Chemistry and Biochemistry, 100, but fretted about losing credit if test — was not publicly reported until Worcester Polytechnic Institute, Worcester, scientists elsewhere produced the element June 1955 in a joint paper by UCRL, Argonne Massachusetts 01609-2280, USA. independently and published first. National Laboratory and Los Alamos e-mail: [email protected] Ghiorso’s concerns were valid. At the Scientific Laboratory, the last of which was Nobel Institute of Physics (NI) in Stockholm, credited with building the weapon2. In References 1. Ghiorso, A. Chem. Eng. News. 81, 174–175 (2003). a cyclotron had been recently upgraded to the paper, the UCRL group unequivocally 2. Ghiorso, A. et al. Phys. Rev. 99, 1048–1049 (1955). 3 produce heavy-ion beams . On 19 February argued this earlier discovery in fallout 3. Atterling, H. Arkiv Fysik. 7, 503–506 (1954). 1954, NI scientists produced 250100 by should take precedence. The first sentence 4. Atterling, H., Forsling, W., Holm, L. W., Melander, L. & Åström, B. of the paper makes that claim crystal clear: Phys. Rev. 95, 585–586 (1954). 5. Harvey, B. G., Thompson, S. G., Ghiorso, A. & Choppin, G. R. Phys. “This communication is a description of Rev. 93, 1129 (1954). the results of experiments performed in 6. Thornton, B. F. & Burdette, S. C. Nat. Chem. 6, 652 (2014). Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts 724 NATURE CHEMISTRY | VOL 9 | JULY 2017 | www.nature.com/naturechemistry ©2017 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved.