The periodic table of chemical elements may welcome a new element to its big family soon. An international team, led by researchers from Lund University, has presented evidence that confirms the existence of a new element with atomic number 115. The provisional name of the element is ununpentium1. The experiment was conducted at the GSI Helmholtz Center for Heavy Ion Research, located in Darmstadt, Germany.
In the periodic table, chemical elements are arranged by their atomic numbers, i.e. the number of protons in the atom’s nucleus. For instance, hydrogen has one proton, iron 26 and the heaviest element on the periodic table is the livermorium with 116 protons.
Elements with more than a hundred protons are called superheavy elements. They are highly unstable, with half-lives ranging from a few minutes to milliseconds. It is impossible to find them in nature since they rapidly decay into more stable and lighter elements. However, researchers have been able to create some of them in the laboratory by colliding lighter elements at high-speeds inside high-energy particle accelerators.
To obtain ununpentium, the scientists bombarded a thin film of americium with calcium ions at the GSI facility. For the first time, the exploitation of a new detector system also allowed for registering photons along with the decay of the new element. The measured photon energies correspond to those expected for X-rays from these products and thus serve as the element’s fingerprint.
The evidence of the existence of ununpentium is not new though. It was already reported in 2004 by Russian and American researchers. Nevertheless, the International Unions of Pure Applied Physics [IUPAP] and Chemistry [IUPAC] concluded that these results were not enough for meeting the criteria for discovery of a new element.
A committee comprised by both IUPAP and IUPAC members will review the new findings to decide whether to acknowledge this discovery. If the result is positive, the new element will adopt a distinctive new name and symbol before it will finally sit in the periodic table right between the flerovium and livermorium.
Besides the X-ray events, the researchers have also obtained further data giving them a deeper insight into the structure and properties of the ununpentium. These findings pave the way towards improved predictions for properties for even heavier elements in the future.
- Upon confirmation, provisional names for new elements are based on a Greco-Latin code for their atomic numbers, e.g., un-un-pentium refers to 1-1-5. [↩]