12th June 2016
Four new additions to the periodic table
The International Union of Pure and Applied Chemistry (IUPAC) has proposed the final names of four new additions to the periodic table.
Following earlier reports that the claims for discovery of these elements have been fulfilled, the discoverers have been invited to propose names and they are now disclosed for public review:
• Nihonium and symbol Nh, for the element 113
• Moscovium and symbol Mc, for the element 115
• Tennessine and symbol Ts, for the element 117
• Oganesson and symbol Og, for the element 118
By Sandbh (Own work) [CC BY-SA 4.0]
The IUPAC Inorganic Chemistry Division has reviewed and considered these proposals and recommends them for acceptance. A five-month public review is now being held, expiring on 8th November 2016, prior to formal approval by the IUPAC Council.
The guidelines for naming elements were recently revised and shared with discoverers to assist in their proposals. Keeping with tradition, a newly discovered element can be named after:
(a) a mythological concept or character (including an astronomical object),
(b) a mineral or similar substance,
(c) a place, or geographical region,
(d) a property of the element, or
(e) a scientist.
Nihonium, with atomic number 113, is a synthetic element (that can be created in a laboratory, but is not found in nature) and is extremely radioactive; its most stable known isotope, ununtrium-286, has a half-life of just 20 seconds. The name comes from one of the pronunciations of the Japanese word for Japan (nihon) that literally means "the Land of Rising Sun". Its research team hopes that pride and faith in science will displace the lost trust of those who suffered from the 2011 Fukushima nuclear disaster.
Moscovium, with atomic number 115, is in recognition of the Moscow region and honours the ancient Russian land that is the home of the Joint Institute for Nuclear Research, where the discovery experiments were conducted using the Dubna Gas-Filled Recoil Separator, in combination with the heavy ion accelerator capabilities of the Flerov Laboratory of Nuclear Reactions. Like nihoniuim, it is extremely radioactive; its most stable isotope has a half-life of only 220 milliseconds. About 100 atoms of moscovium have been observed to date.
Tennessine, with atomic number 117, recognises the contribution of the Tennessee region, including Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee at Knoxville, to superheavy element research, including the production and chemical separation of unique actinide target materials for superheavy element synthesis at the High Flux Isotope Reactor (HFIR) and Radiochemical Engineering Development Centre.
Oganesson, with atomic number 118, was discovered by teams at the Joint Institute for Nuclear Research, Dubna (Russia) and Lawrence Livermore National Laboratory (USA). The name is in line with the tradition of honouring a scientist and recognises Professor Yuri Oganessian (born 1933) who played a leading role in discovering the heaviest elements of the periodic table, made significant advances in the nuclear physics of superheavy nuclei and produced experimental evidence for the "island of stability". Oganesson has the highest atomic number and mass of all known elements. It is extremely unstable, due to its high mass, and since 2005, only three or possibly four atoms of the isotope 294Uuo have been detected.
"It is a pleasure to see that specific places and names (country, state, city, and scientist) related to the new elements is recognised in these four names. Although these choices may perhaps be viewed by some as slightly self-indulgent, the names are completely in accordance with IUPAC rules", commented Jan Reedijk, who corresponded with each team and invited the discoverers to make proposals. "In fact, I see it as thrilling to recognise that international collaborations were at the core of these discoveries and that these new names also make the discoveries somewhat tangible."
Ultimately, and after the lapse of the public review in November, the final recommendations will be published in the journal Pure and Applied Chemistry.
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