Specifications: Darmstadtium Darmstadtium, formerly called ununnilium or eka-platinum, is a chemical element with the symbol Ds and atomic number 110. It is one of the so-called super-heavy atoms. This synthetic element quickly decays: its isotopes of mass 267 to 273 have half-lives measured in microseconds. Heavier isotopes of darmstadtium, of mass 279 and 281, were synthesized later and are more stable, with half-lives of 180 milliseconds and 11.1 seconds, respectively.