Hassium
Hassium is a synthetic superheavy transition metal made only in particle accelerators, one atom at a time — it has no natural existence anywhere on Earth. It sits in group 8 of the periodic table, directly below osmium, and is predicted to be an extremely dense metal, though far too few atoms have ever been produced to actually weigh or handle a sample. Like its neighbors on the periodic table, every atom of hassium ever created has decayed away almost immediately.
- Group · Period
- 8 · 7
- At room temp
- solid
- Melts at
- Not yet available
- Density
- Not yet available
- Discovered
- 1984
Uses
Hassium has no practical, industrial or medical use, and given how difficult and fleeting its production is, it never will. Its only real significance is as an object of fundamental research: synthesizing and studying hassium helps physicists probe the stability of superheavy nuclei and search for the theorized “island of stability,” a region of the chart of nuclides where longer-lived superheavy atoms might exist.
History
Hassium was first synthesized in 1984 by researchers at the GSI Helmholtz Centre in Darmstadt, Germany, who fired accelerated nuclei at a metal target and identified the handful of resulting hassium atoms through their radioactive decay signatures. It was named after Hesse, the German state in which the laboratory sits, continuing a tradition of naming elements after the places where they were discovered. The name was formally adopted by the International Union of Pure and Applied Chemistry in 1997.
Fun facts
- Hassium is named after Hesse (Hessen), the German state where the GSI research laboratory that helped synthesize it is located.
- Hassium is predicted to be one of the densest elements on the periodic table, denser even than osmium — but this has never been measured directly, since only single atoms have ever existed at once.
- Even the most stable known isotopes of hassium last only on the order of seconds before decaying away.
Frequently asked questions
Does hassium have any real-world use?
No — hassium exists purely for scientific research. It has no commercial, industrial or medical applications, and its extreme rarity and instability mean it never could.
How is hassium produced?
Hassium is made by accelerating a beam of nuclei to very high speed and firing it at a target of another element, so that the two nuclei occasionally fuse into a single hassium nucleus. Physicists then identify a successful fusion by tracking the specific chain of radioactive decays that follows.
Why is hassium's density only a prediction?
Because every atom of hassium ever made has existed alone and decayed within seconds, there has never been enough of it in one place — let alone long enough — to measure its density directly. The figure chemists cite comes from calculations based on its position in the periodic table, not direct observation.
Isotopes
13 known isotopes
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| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Hs-269 | — | 13 s | Alpha decay (100%), Spontaneous fission (5%) | 124,493 keV | 7,294 keV | 3.51 × 10-17 eV |
| Hs-270 | — | 7.6 s | Alpha decay (50%), Spontaneous fission (50%) | 125,112 keV | 7,295 keV | 6.00 × 10-17 eV |
| Hs-278 | — | 19 m | Spontaneous fission (100%), Alpha decay (50%) | 143,220 keV | 7,252 keV | 4.00 × 10-19 eV |
Show all 13 isotopes
| Hs-263 | — | — | Alpha decay (100%) | 119,678 keV | 7,295 keV | — |
| Hs-264 | — | 0.8 ms | Alpha decay (50%), Spontaneous fission (50%) | 119,563.17 keV | 7,298.38 keV | 5.70 × 10-13 eV |
| Hs-265 | — | 2.0 ms | Alpha decay (100%), Spontaneous fission (1%) | 120,900.25 keV | 7,296.25 keV | 2.28 × 10-13 eV |
| Hs-266 | — | 2.97 ms | Alpha decay (76%), Spontaneous fission (24%) | 121,139.68 keV | 7,298.26 keV | 1.54 × 10-13 eV |
| Hs-267 | — | 43 ms | Alpha decay (100%) | 122,658 keV | 7,295 keV | 1.06 × 10-14 eV |
| Hs-268 | — | 0.4 s | Alpha decay (100%) | 122,968 keV | 7,297 keV | 1.14 × 10-15 eV |
| Hs-271 | — | — | Alpha decay (100%), Spontaneous fission (15%) | 127,691 keV | 7,288 keV | — |
| Hs-273 | — | 0.51 s | Alpha decay (100%), Spontaneous fission (12.5%) | 131,767 keV | 7,279 keV | 8.95 × 10-16 eV |
| Hs-275 | — | 0.20 s | Alpha decay (100%), Spontaneous fission (20%) | 136,492 keV | 7,268 keV | 2.28 × 10-15 eV |
| Hs-277 | — | 3 ms | Spontaneous fission (100%), Alpha decay (50%) | 141,375 keV | 7,256 keV | 1.52 × 10-13 eV |