in your element Einsteinium declassified Discovered during secret testing by the United States, Joanne Redfern tells us about element 99 and why its namesake cautioned against the very technology that led to its creation.

n the first of November 1952, in a top causes einsteinium to glow7. Furthermore, secret test known as Mike, the United because it decays rapidly into berkelium OStates detonated the ‘Sausage’ — the and californium, samples of einsteinium are world’s first hydrogen bomb. The explosion nearly always contaminated. annihilated the entire Pacific island of Einsteinium is mainly used to make Elugelab, but it wasn’t all devastation; at heavier elements, such as mendelevium — the same time it created two new elements first discovered by Ghiorso’s team when that their discoverers would later name bombarding 253Es with alpha particles. In einsteinium and fermium. The explosion was addition, scientists have used its radiation colossal, being more powerful than all of the to study accelerated aging and radiation high explosives used in World Wars I and II damage, and have examined its potential combined1. In an instant, an enormous for medical treatments, although not number of neutrons (around 1024–1025 cm–2, commercially7. Outside of basic research, ref. 2) blasted into the uranium atoms used einsteinium has no practical use. So although in the bomb. Some of these atoms captured its name lends it a familiarity, most of us KEYSTONE-FRANCE / GAMMA-KEYSTONE / GETTY IMAGES / GAMMA-KEYSTONE KEYSTONE-FRANCE 15 neutrons each — resulting in very will never come across even a single atom of heavy uranium isotopes — before rapidly Einstein warns of the dangers of developing the einsteinium in our lifetimes. undergoing seven beta decays. The result was hydrogen bomb (12th February 1950). Einsteinium kicked off a trend for naming a new element with an atomic number of new elements after famous scientists, and 99 and an atomic mass of 253. it is hard to imagine a scientist who would Radioactive debris — including They discovered that bombarding 238U with not appreciate this honour. But for Einstein, element 99 — mushroomed out of the nitrogen ions produced a short-lived isotope this particular element seems like an ironic explosion in a 60-mile-wide cloud. Keen of element 99, and they published their choice; he was a pacifist, vehemently opposed to understand more about the science findings in 1954 with a note to acknowledge to the development of the hydrogen bomb. He of thermonuclear explosions, the US that prior work on the element existed5. A few even recorded a statement for US television Government sent fighter jets flying through months later the Mike test was declassified, show Today with Mrs. Roosevelt (pictured) the cloud to sample the radioactive fall-out allowing Ghiorso to report his team’s earlier in which he warned that the hydrogen bomb by using special filter papers attached to discovery in 19556. He also had the honour of could annihilate life on earth. So how did he their wing tanks2. The detailed analysis choosing the name, einsteinium (Es). feel about a bomb-born element being named fell to Albert Ghiorso and colleagues at Today scientists produce einsteinium by after him? We will never know. He died just the University of California, Berkeley — bombarding plutonium with neutrons in a a few months before Ghiorso announced according to Ghiorso, the results were nuclear reactor, then allowing the resulting einsteinium to the world. ❐ entirely unexpected3. isotopes to undergo beta decay. This is a slow The team detected a unique radiation process. Indeed, it took until 1961 (nine years JOANNE REDFERN is a science and signal that they deduced must have come after its initial discovery) before scientists medical writer based in Cambridge, UK. from the hitherto unknown element 99. They managed to make enough einsteinium to e-mail: [email protected] later detected the same signal (and that of observe its form as a silvery metal4. References element 100) from radioactive coral debris As well as being scarce, einsteinium is 1. Nuclear Weapon Archive (accessed 14 August 2016); gathered from neighbouring islands. The difficult to study because it self-destructs. It http://go.nature.com/2fAKydM miniscule amount of element 99 (fewer than has nearly 20 different isotopes, all of which 2. Hoffman, D. C., Ghiorso, A. & Seaborg, G. T. The Transuranium 4 252 People: The Inside Story Ch. 6 (Imperial College Press, 2000). 200 atoms in total ) made the discovery all the are radioactive. The most stable, Es, has a 3. Ghiorso, A. Einsteinium and Fermium (Chemical and more remarkable. Frustratingly, the team were half-life of about 472 days, but it is difficult to Engineering News, American Chemical Society, 2003); not allowed to say a word as the details of the produce and is only available in tiny amounts. http://go.nature.com/2fdCSdz Mike test remained classified. 253Es is the most common isotope, but it has 4. Emsley, J. Nature’s Building Blocks: An A-Z Guide to the Elements (Oxford Univ. Press, 2011). To get around this, Ghiorso’s team set a half-life of only 20 days. It releases gamma 5. Ghiorso, A., Rossi G. B., Harvey, B. G. & Thompson, S. G. about making element 99 by other means. rays and X-rays when it decays, damaging Phys. Rev. 93, 257 (1954). its crystal lattice and hampering any X-ray 6. Ghiorso, A. et al. Phys. Rev. 99, 1048 (1955). 7. Haire, R. G. in The Chemistry of the Actinide and Transactinide crystallographic analysis. The intense Elements 3rd edn (eds Morss, L. R., Edelstein, N. M. & Fuger, J.) release of energy (1000 W per gram) also 1577–1620 (Springer, 2006). Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn 113 Fl 115 Lv 1168 NATURE CHEMISTRY | VOL 8 | DECEMBER 2016 | www.nature.com/naturechemistry ©2016 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved.