Overview

Hassium was first created in 1984 at the GSI laboratory in Darmstadt by the team of Peter Armbruster and Gottfried Munzenberg, by fusing iron and lead nuclei. It was named after the German state of Hesse, in Latin Hassia, where the Darmstadt laboratory lies. Hassium is an intensely radioactive synthetic metal, existing only for fractions of a second, though its chemistry has been studied on a handful of atoms and found to match expectations for its group. Made by fusing iron and lead nuclei, hassium exists for at most seconds and usually a fraction of a second, so that every atom must be identified individually by the chain of radioactive decays it leaves behind.

A landmark experiment in 2001 succeeded in studying hassium's actual chemistry despite having only a handful of atoms to work with, confirming that hassium tetroxide behaves much like the corresponding osmium compound, volatile and chemically similar, direct evidence that the periodic table's predicted trends hold even for elements that exist for only fractions of a second and can never be gathered in bulk. Such single-atom chemistry experiments, requiring the coordinated effort of large international teams, remain among the most technically demanding in all of modern science.