Hassium
Element 108 · Transition Metal
Hassium is the group 8 transactinide, expected to mirror osmium. Experiments with a few atoms demonstrated that it forms hassium tetroxide, a volatile +8 oxide analogous to osmium tetroxide, confirming its place in the periodic table. Its longest-lived isotope has a half-life of about 16 milliseconds for the commonly made isotope, with longer-lived ones near 10 seconds. Properties are predicted, with very limited experimental data. Hassium is radioactive, with its isotopes decaying in milliseconds to seconds.
Key facts
| Atomic number | 108 |
|---|---|
| Atomic weight | [277] |
| Category | Transition Metal |
| Group / Period | 8 / 7 |
| Block | d |
| Electron configuration | [Rn] 5f14 6d6 7s2 |
| Common oxidation states | +8 (predicted) |
| State at STP | Solid |
Occurrence
Hassium is entirely synthetic, first produced in 1984 at GSI Darmstadt by fusing iron-58 with lead-208.
Applications
Few-atom gas-phase chemistry
Testing predictions of superheavy volatility
No commercial applications
Common compounds
- Hassium tetroxide (HsO4, observed)
- Hassium dioxide (HsO2, predicted)
Hassium is named after the German state of Hesse, where the GSI laboratory that discovered it is located.
Data source: IUPAC standard atomic weights 2021