Hassium

Named after the German state of Hesse, and one of the heaviest elements whose chemistry has been tested.

At a glance

Symbol: Hs
Atomic number: 108
Mass number of its longest-lived isotope: [269]
Group: 8
Period: 7
Family: transition metal
Electron configuration: [Rn] 5f¹⁴ 6d⁶ 7s² (predicted)
Electronegativity: not measured
Common ions: predicted +8, like osmium

On the table

Period 7, group 8. The other transition metals are tinted, and every cell opens its own article.

Electrons and bonding

Only a handful of atoms have ever been made, each lasting seconds or less, so its chemistry is predicted from its place in the table rather than measured.

Properties

State at 25 °C: not known
Physical properties: none measured; no more than a few atoms have ever existed at once

Where it is found

Not found in nature. It is made a few atoms at a time in particle accelerators by fusing lighter nuclei, and each atom decays within seconds to hours.

Discovery and name

Armbruster and Münzenberg's team at GSI in Darmstadt made it in 1984 by fusing iron and lead nuclei. It was named after Hassia, the Latin name of Hesse, the German state where GSI is located.

What it is used for

Research only. In 2001 chemists made hassium tetroxide from a handful of atoms and found it behaves like osmium tetroxide, just as its place in the table predicts.