English Isotopes of hassium Cited by user Double sharp on 29 Mar 2013 Hassium (Hs) is an artificial element, and thus a standard atomic mass cannot be given.
English Isotopes of darmstadtium Cited by user Nergaal on 13 Feb 2012 Darmstadtium (Ds) is an artificial element, and thus a standard atomic mass cannot be given.