Researchers in Russia and the US have collaborated to synthesize a new element with atomic number 117. The project was led by Yuri Oganessian, 1 of the Joint Institute for Nuclear Research in Dubna, Russia, who also spearheaded the discoveries of elements 113-116 and 118. He and his Dubna colleagues worked with US researchers from Oak Ridge National Laboratory, Lawrence Livermore National Laboratory, Vanderbilt University, and the University of Nevada, Las Vegas.
The synthesis was done with an eye toward the eagerly anticipated island of stability, a region just off the chart of known nuclides and centered around the next proton number Z and neutron number N that correspond to filled nucleon shells. Theorists agree that the target value of N is 184 but disagree on the value of Z: It could be 114, 120, or 126.
The isotopes of element 117, with lifetimes measured in milliseconds, were not especially...
