Darmstadtium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It was named after the city of Darmstadt, where it was discovered.
Darmstadtium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 269Ds in 1994. There are 7 or 8 known radioisotopes and 2 or 3 known isomers. The longest-lived isotope is 281Ds with a half-life of 9.6 seconds.