Roentgenium
[Rn] 5f¹⁴ 6d⁹ 7s² · 2 · 8 · 18 · 32 · 32 · 17 · 2
An element named after Wilhelm Röntgen and discovered exactly a century after X-rays. Calculations predict roentgenium could be the first metal to hold a −1 oxidation state in a stable compound.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 111
- Atomic mass
- 282 а.е.м. ≈
- Electron configuration
- [Rn] 5f¹⁴ 6d⁹ 7s²
- Electrons per shell
- 2 · 8 · 18 · 32 · 32 · 17 · 2
- Block
- d-block
- Group
- Copper group
- Period
- 7
- Electronegativity (Pauling)
- no data
- Electronegativity (Allen)
- no data
- Atomic radius
- no data
- Covalent radius
- 121 pm
- Van der Waals radius
- no data
- Ionisation energy 1
- 1 020 kJ/mol ≈
- Electron affinity
- no data
- Common oxidation states
- +3
- Oxidation states
- +3
Physical properties
- State at 25 °C
- unknown
- Density
- 23 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
- body-centred cubic (bcc) ≈
- 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 |
|---|---|---|---|
| 281Rg | — | 26 s | СД |
| 282Rg | — | 1.67 min | α |
Roentgenium-282, half-life about 100 seconds, is the longest-lived known isotope.
Discovery
- Year of discovery
- 1994
- Discovered by
- Sigurd Hofmann and colleagues
- Where
- Darmstadt, Germany
- Origin of the name
- after Wilhelm Röntgen
History
Hofmann and colleagues synthesised element 111 at GSI in December 1994, a month after darmstadtium. The name was confirmed in 2004, on the 110th anniversary of the X-ray.
Where it occurs
Absent from nature.
How it is produced
By nuclear fusion: bismuth-209 bombarded with nickel-64 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
Curiosities
- Röntgen refused to patent his discovery, holding that it belonged to humanity.
- Element 111 was discovered in the centenary year of X-rays — the coincidence that fixed its name.
- Calculations predict roentgenium has an anomalously high electron affinity, above gold's.
- Roentgenium honours the very first Nobel laureate in physics.