Hassium
[Rn] 5f¹⁴ 6d⁶ 7s² · 2 · 8 · 18 · 32 · 32 · 14 · 2
The heaviest element on which a genuine chemical experiment has been performed. In 2002 hassium was shown to form a volatile tetroxide, as osmium does — periodicity confirmed at the edge of the table.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 108
- Atomic mass
- 269 а.е.м. ≈
- Electron configuration
- [Rn] 5f¹⁴ 6d⁶ 7s²
- Electrons per shell
- 2 · 8 · 18 · 32 · 32 · 14 · 2
- Block
- d-block
- Group
- Iron group
- Period
- 7
- Electronegativity (Pauling)
- no data
- Electronegativity (Allen)
- no data
- Atomic radius
- no data
- Covalent radius
- 134 pm
- Van der Waals radius
- no data
- Ionisation energy 1
- 730 kJ/mol ≈
- Electron affinity
- no data
- Common oxidation states
- +8
- Oxidation states
- +8
Physical properties
- State at 25 °C
- unknown
- Density
- 28 g/cm³ ≈
- Melting point
- no data
- Boiling point
- no data
- Speed of sound
- no data
Thermal properties
- Heat of fusion
- no data
- Heat of vaporisation
- no data
- Specific heat capacity
- no data
- Thermal conductivity
- no data
Mechanical properties
- Young's modulus
- no data
- Shear modulus
- no data
- Bulk modulus
- no data
- Poisson ratio
- no data
- Mohs hardness
- no data
- Brinell hardness
- no data
Electrical and magnetic properties
- Electrical resistivity
- no data
- Magnetic ordering
- no data
- Curie point
- no data
- Néel point
- no data
- Superconducting point
- no data
Crystal structure
- Crystal structure
- hexagonal close-packed (hcp) ≈
- Lattice constants
- no data
Abundance
- In the crust
- 0 mg/kg
- In the ocean
- 0 mg/L
- In the universe
- 0 mg/kg
- In the human body
- 0 mg/kg
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 269Hs | — | 16 s | α |
| 270Hs | — | 22 s | α |
Hassium-269 and hassium-270 live 10 to 20 seconds each. Hassium-270 is thought to be doubly magic, which would explain its relative stability.
Discovery
- Year of discovery
- 1984
- Discovered by
- Peter Armbruster, Gottfried Münzenberg and colleagues
- Where
- Darmstadt, Germany
- Origin of the name
- from Hassia, the Latin name for the German state of Hesse
History
Münzenberg and Armbruster synthesised element 108 at Darmstadt in 1984. The name comes from Hassia, the Latin for the German state of Hesse, where GSI stands.
Where it occurs
Absent from nature.
How it is produced
By nuclear fusion: lead-208 bombarded with iron-58 ions. It is made one atom at a time.
Role in living things
No biological role.
Safety
Only single atoms are ever handled.
Uses
Fundamental research into periodicity at the limit of the table
Curiosities
- Hassium is the heaviest element whose chemistry has been studied experimentally.
- HsO₄, hassium tetroxide, behaves almost exactly like osmium tetroxide — the periodic law holding at box 108.
- Hassium-270 may be a doubly magic nucleus: 108 protons and 162 neutrons.
- The name comes from the Latin for the German state of Hesse.