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Livermorium and flerovium: New names for heavy elements

June 01, 2012|By Thomas H. Maugh II
  • Element 114 has been officially named flerovium and element 116 livermorium.
Element 114 has been officially named flerovium and element 116 livermorium. (Lawrence Livermore National…)

The super-heavy elements 114 and 116 have officially been recognized by the International Union of Pure and Applied Chemistry, the official arbiter of chemical names, and have been named in honor of the U.S. and Russian institutions where they were jointly discovered. Element 116 has been named livermorium with the symbol Lv in honor of the Lawrence Livermore National Laboratory and the nearby city of Livermore.

Element 114 has been named flerovium, with the symbol Fl, in honor of the Flerov Laboratory on Nuclear Reactions in Dubna. Georgiy N. Flerov, who died in 1990, was a renowned physicist who discovered the spontaneous fission of uranium and was a pioneer in the creation of super-heavy elements. He was the founder of the Joint Institute for Nuclear Research, which was renamed FLNR in his honor after his death.

Only 92 elements exist in nature, but researchers have now created and named 20 more, including elements 114 and 116. Elements 113, 115 and 117 have also been created, but their existence has not been officially recognized and they have not been named. All of the man-made elements have short half-lives, which is why they are not found in nature. In general, the heavier the element, the shorter its half-life. Theoretical physicists think there may be an "island of stability" among certain super-heavy elements, giving them a longer half-life. Researchers had hoped that might prove to be the case with element 118, but that did not pan out. Physicists are now pinning their hopes on elements with atomic weights of 120 and higher.

Researchers created flerovium by bombarding a target of plutonium-244 with ions of calcium-48, producing Fl-289, which had a half-life of 30 seconds. Fl-289 has 114 protons in its nucleus and 175 neutrons. It decays into element 112, copernicium, which has a half-life of 28 milliseconds. In separate experiments the teams bombarded plutonium with calcium ions at a higher energy, which forced the resulting element to bleed off four neutrons, producing Fl-285. Those atoms decayed in less than a fifth of a second to copernicium-281. That decayed in less than a fifth of a second to darmstadtium-277, which lived a mere 0.08 seconds before becoming hassium-273. That, in turn, lasted a third of a second before becoming seaborgium-269, which lasted 3 minutes and five seconds before becoming rutherfordium-265, which fissioned after 2.5 minutes.

Livermorium was produced by smashing calcium-48 ions into a target of curium-248, producing Lv-292. Atoms of the element lasted from 50 to 125 milliseconds before decaying into Fl-288.

The official names will be published in the July issue of the IUPAC journal, Pure and Applied Chemistry.

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Twitter/@LATMaugh

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