The International Union of Pure and Applied Chemistry (IUPAC) has opened a five-month long public comment and review period of the names recommended for elements 113, 115, 117 and 118, the discoveries of which were announced late last year.
Researchers at RIKEN Nishina Center for Accelerator-Based Science (Japan) have proposed the name nihonium (Nh) for element 113, the first element discovered in an Asian country. Nihon is one of the two ways to say “Japan” in Japanese, and literally means “the Land of Rising Sun.”
Lawrence Livermore National Laboratory (LLNR) and the Joint Institute for Nuclear Research in Dubna, Russia (JINR) were credited late last year for discovering elements 115 and 118. LLNL, JINR, Oak Ridge National Laboratory (ORNL, CSA CSM), Vanderbilt University and the University of Nevada, Las Vegas were credited with the discovery of element 117.
Moscovium (Mc) is the recommended name for element 115, recognizing the Moscow region and honoring the ancient Russian land that is home to JINR, 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.
Tennessine (Ts) is proposed for element 117, recognizing the contribution of Tennessee research centers ORNL, Vanderbilt and the University of Tennessee to superheavy element research, including the production and chemical separation of unique actinide target materials for superheavy element synthesis at ORNL’s High Flux Isotope Reactor (HFIR) and Radiochemical Engineering Development Center (REDC).
The provisional name for element 118 is Oganesson (Og) in recognition of the pioneering contributions of Yuri Oganessian to superheavy element research. Oganessian’s vision and determination created this opportunity for the significant expansion of the periodic table and knowledge of superheavy nuclei.
“It is a pleasure to see that specific places and names related to the new elements is recognized 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,” says Jan Reedijk, president of the Inorganic Chemistry Division of IUPAC, who corresponded with the various laboratories and invited the discoverers to make proposals. “In fact, I see it as thrilling to recognize that international collaborations were at the core of these discoveries and that these new names also make the discoveries somewhat tangible.”
The guidelines for naming elements were recently revised by IUPAC and shared with the discoverers to assist in proposals. Keeping with tradition, the newly discovered elements could be named after a mythological concept or character (including an astronomical object); a mineral or similar substance; a place, or geographical region; a property of the element, or a scientist.
Additionally, the new names had to have an ending that reflected and maintained historical and chemical consistency—“-ium” for elements belonging to groups 1-16, “-ine” for elements of group 17 and “-on” for elements of group 18.
The provisional names will undergo a statutory period for public review before the names and symbols can be finally approved by the IUPAC Council later this year and thereafter published in the IUPAC journal Pure and Applied Chemistry.
“I’m proud of all of the hard work that this group has done over the years performing these experiments,” says Dawn Shaughnessy, LLNL’s principal investigator for the Heavy Element Group. “It’s a huge accomplishment for the entire group that we are recognized for our efforts in accomplishing these highly difficult experiments and for the years of work it takes to successfully create a new chemical element.”
The new elements and nuclei will complete the seventh row of the periodic table, and provide evidence for the long sought “island of stability” for superheavy elements. Two members of the team, JINR and LLNL, were previously credited with the discovery of elements 114 (flerovium) and 116 (livermorium).
The concept of the “island of stability” was originally proposed in the 1960s. It predicts increased stability for superheavy nuclei at higher neutron and proton numbers. The new nuclei produced in this research exhibit substantially increased lifetimes consistent with approaching the island.
These new elements were discovered using the “hot fusion” approach, developed and implemented by Oganessian at JINR. This approach involves heavy ion reactions of an intense, high-energy calcium beam on rare actinide targets including berkelium and californium at the Dubna Gas-Filled Recoil Separator.