Atomic number 108 · Transition metal
Hassium Hs
Hassium is a superheavy element named after the German state of Hesse. It belongs to group 8 with iron, ruthenium and osmium, and experiments with just a handful of atoms showed that, like osmium, it forms a volatile tetroxide, a striking demonstration that superheavy elements still follow the logic of the periodic table.
Key properties
| Atomic number | 108 |
|---|---|
| Atomic weight | [269] (No stable isotope; mass number of a representative isotope in brackets) |
| Category | Transition metal |
| Group | 8 |
| Period | 7 |
| Block | d |
| State (25 °C, 1 atm) | Solid |
| Melting point | — |
| Boiling point | — |
| Density | — |
| Electronegativity (Pauling) | — |
| Atomic radius (van der Waals) | — |
| First ionization energy | — |
| Electron affinity | — |
| Oxidation states | 8, 6, 5, 4, 3, 2 |
| Discovered | 1984 |
Electron configuration
- Condensed
- [Rn]7s2 5f14 6d6
- Full
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d6 7s2
- Electrons per shell
- 2 · 8 · 18 · 32 · 32 · 14 · 2
Orbital diagram
Position in the table
Discovery
A Dubna group tried to make element 108 from 1978 onwards and claimed success in 1984. Later in 1984 Peter Armbruster and Gottfried Münzenberg's team at GSI in Darmstadt bombarded lead-208 with iron-58 ions, produced hassium-265 and confirmed it through its decay chain. In 1993 the joint working group judged the GSI work to be the definitive discovery.
In 1992 GSI proposed the name hassium, after the state where the laboratory stands, and it was made official in 1997. In 2001 an international team working at GSI reacted a few hassium atoms with oxygen to form hassium tetroxide (HsO₄). It behaved much like osmium tetroxide, chemically confirming hassium's place in group 8.
Origin of the name
The name comes from Hassia, the Latin name of Hesse (Hessen), the German state that is home to GSI. The symbol is Hs. With meitnerium and darmstadtium it forms a cluster of elements whose names are linked to Germany.
Main uses
- Basic research: It has no uses outside science.
- Chemistry: The hassium tetroxide experiment stands as one of the landmark successes of superheavy gas-phase chemistry.
- Nuclear structure: Hassium-270, with 108 protons and 162 neutrons, is studied as a candidate 'doubly magic' nucleus for deformed (non-spherical) shapes, where both numbers confer extra stability.
Isotopes
There are no stable isotopes. The longest-lived known isotopes, such as hassium-269 and hassium-270, have half-lives of the order of ten seconds. Hassium-265, the isotope of the discovery, lasts only about two milliseconds.
In everyday life
It does not exist in nature; only a few atoms at a time are made in accelerators and they decay almost immediately, so it has no connection with daily life or health.
Good to know
- Hassium's name comes from Hassia, the Latin name for Hesse.
- In 2001 a few atoms of hassium were turned into hassium tetroxide, confirming its kinship with osmium.
- Hassium-270 is a candidate doubly magic nucleus for deformed shapes.
Same group (8)
Data sources · Properties: PubChem Periodic Table (US NIH/NLM public data) · Atomic weights: CIAAW 2024 abridged standard atomic weights · Names: Wikidata (CC0); Korean names follow the Korean Chemical Society. Retrieved 2026-09-23.