Hassium is a synthetic chemical element; it has symbol Hs and atomic number 108. It is highly radioactive: its most stable known isotopes have half-lives of about ten seconds. One of its isotopes, 270
GSI's linear particle accelerator UNILAC, where hassium was discovered and where its chemistry was first observed
Energy levels of outermost orbitals of hassium and osmium atoms in electronvolts, with and without taking relativistic effects into account. Note the lack of spin–orbit splitting (and thus the lack of distinction between d3/2 and d5/2 orbitals) in nonrelativistic calculations.