Periodic Table of Elements (Image by Los Alamos National Laboratory)
Note: This story was updated at 10:56 p.m. Jan. 6.
Four new elements have been added to the periodic table, filling the seventh row, or period, and Oak Ridge National Laboratory played a role in discovering two of them.
The discovery and assignment of elements with atomic numbers 113, 115, 117, and 118 was announced on December 30 by the International Association of Pure and Applied Chemistry. The discoveries have been officially verified.
ORNL participated in the discovery of elements 115 and 117 in a collaboration between the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California.
The discoverers, who also include researchers in Japan, will now be invited to suggest permanent names and symbols.
For now, the elements are known as:
- Element 113—ununtrium, Uut, which was discovered by the RIKEN collaboration team in Japan;
- Element 115—ununpentium, Uup, which was discovered by the Joint Institute for Nuclear Research, Lawrence Livermore National Laboratory, and Oak Ridge National Laboratory;
- Element 117—ununseptium, Uus, which was discovered by the Joint Institute for Nuclear Research, Lawrence Livermore National Laboratory, and Oak Ridge National Laboratory; and
- Element 118—ununoctium, Uuo, which was discovered by the Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory.
“A particular difficulty in establishing these new elements is that they decay into hitherto unknown isotopes of slightly lighter elements that also need to be unequivocally identified” said Professor Paul J. Karol, chair of the fourth IUPAC/IUPAP Joint Working Party, or JWP. “But in the future we hope to improve methods that can directly measure the atomic number, Z.”
The IUPAP is the International Union of Pure and Applied Physics.
The periodic table was devised by Russian chemist Dmitri Mendeleev in 1869, and it categorizes chemical elements according to their atomic number.
The new elements were created by using particle accelerators to shoot beams of nuclei at other, heavier, target nuclei, according to National Public Radio. The new elements’ existence was confirmed by further experiments that reproduced them.
The resulting superheavy elements, like others of their kind, exist for only a fraction of a second before decaying into lighter atoms, New Scientist reported.
The last time new elements were added to the periodic table was in 2011, when elements 114 (flerovium, or Fl) and element 116 (livermorium or Lv) were added.
“The chemistry community is eager to see its most cherished table finally being completed down to the seventh row. IUPAC has now initiated the process of formalizing names and symbols for these elements, (which are) temporarily named,” Professor Jan Reedijk, president of the Inorganic Chemistry Division of IUPAC, said in a press release from that organization.
The Riken Institute said element 113, which exists for less than a thousandth of a second, is “the first element on the periodic table found in Asia,” NPR reported.
Apart from helping to flesh out the periodic table, the creation of superheavy elements puts theories of atomic structure to the test, and might one day yield stable new elements with strange properties, New Scientist said.
The reports by the Joint Working Party will be published in an early 2016 issue of the IUPAC journal Pure and Applied Chemistry, or PAC.
“The JWP has reviewed the relevant literature pertaining to several claims of these new elements,” the press release said.
Several studies published from 2004 to 2012 have been construed as sufficient to ratify the discovery and priority of element 113, the JWP said.
In the same report, the JWP also concluded that the collaborative work between scientists from the Joint Institute for Nuclear Research, Lawrence Livermore National Laboratory, and Oak Ridge National Laboratory, starting in 2010, and subsequently confirmed in 2012 and 2013, had met the criteria for discovery of the elements with atomic numbers Z=115 and Z=117.
Update: Oak Ridge Today has published a newer story with more information on ORNL’s role in the discovery of the two new elements. See that story here.
In a separate PAC article, the Dubna–Livermore collaboration that started in 2006 is reported as having satisfied the criteria for discovery of element Z=118, the press release said.
The proposed names and symbols for the new elements will be checked by the Inorganic Chemistry Division of IUPAC for consistency, translatability into other languages, possible prior historic use for other cases, etc.
The IUPAC said mew elements can be named after a mythological concept, a mineral, a place or country, a property or a scientist. After acceptance by the Inorganic Chemistry Division, the names and two-letter symbols will be presented for public review for five months, before the highest body of IUPAC, the Council, will make a final decision on the names of these new chemical elements and their two-letter symbols and their introduction into the Periodic Table of the Elements.
“As the global organization that provides objective scientific expertise and develops the essential tools for the application and communication of chemical knowledge for the benefit of humankind, the International Union of Pure and Applied Chemistry is pleased and honored to make this announcement concerning elements 113, 115, 117, and 118 and the completion of the seventh row of the periodic table of the elements,” said IUPAC President Mark C. Cesa, adding that, “we are excited about these new elements, and we thank the dedicated scientists who discovered them for their painstaking work, as well the members of the IUPAC/IUPAP Joint Working Party for completing their essential and critically important task.”
More information will be added as it becomes available.
Photo by ORNL
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