Periodic table › Roentgenium
1. Identity and classification
Synthetic superheavy element; macroscopic appearance unconfirmed (only single atoms synthesized in particle accelerators)
- Name and symbol
- Roentgenium (Roentgenium) · Rg
- Atomic number
- 111
- Relative atomic weight / mass number
- [282]
- Group · period · block
- 11 · 7 · d
- Category
- Unknown Properties
- State near room temperature
- Unknown
- Stable isotopes
- No stable isotopes
- CAS number
- 54386-24-2
Square brackets [A] indicate a representative isotope mass number, not an average atomic weight. Neutron counts differ between isotopes.
2. Atomic structure and electron configuration
- Protons · electrons in a neutral atom
- 111 · 111
- Neutrons in reference isotope
- 171 (282Rg)
- Full electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d⁹ 7s²- Abbreviated configuration
[Rn]7s² 5f¹⁴ 6d⁹ (predicted)- Electrons per shell
- 2, 8, 18, 32, 32, 17, 2
- Listed oxidation states
- 5, 3, 1, -1
- Electronegativity
- Not established
- First ionization energy
- Not established · Not established
- Electron affinity
- Not established
- Covalent radius
- 121 pm
- van der Waals radius
- Not established
Configurations of superheavy elements may include theoretical predictions. Different definitions of atomic radius are not interchangeable.
3. Physical and thermal properties
- Density
- Not established
- Melting point
- Not established
- Boiling point
- Not established
- Crystal structure
- Unknown / Predicted
- Specific heat
- Not established
- Thermal conductivity
- Not established
- Enthalpy of fusion
- Not established
- Enthalpy of vaporization
- Not established
- Magnetic ordering
- Unknown
- Mohs hardness
- Not established
- Speed of sound
- Not established
Density and structure depend on temperature, pressure and allotrope. 25°C is a room-temperature reference, not STP. Unestablished values are not zero.
4. Chemical behavior and compounds
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
Selected compounds: RgO / Rg₂O₃ (Oxide) · RgClₙ (Chloride) · RgFₙ (Fluoride)
Reaction reference
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
Bulk reactions are not established; experiments involve small numbers of radioactive atoms.
5. Isotopes
| Isotope | Status | Natural abundance | Half-life |
|---|---|---|---|
| 282Rg | Radioactive | — | 100 s |
Half-life units: s seconds, m minutes, h hours, d days, Y years. A dash means no natural-abundance value is given, not zero. Listed records are selected ground states; metastable states are distinct.
6. Discovery and occurrence
- Discovery
- 1994 CE
- Scientists associated with discovery
- GSI Helmholtz Centre for Heavy Ion Research (Sigurd Hofmann et al.)
- Location
- Germany (Darmstadt)
- Origin
- Synthetic
- Listed crustal abundance
- 0 ppm
Minerals and naming reference
Synthesized via heavy-ion fusion (²⁰⁹Bi + ⁶⁴Ni)
Named from scientific/historical roots associated with Roentgenium (Rg), discovered or characterized by GSI Helmholtz Centre for Heavy Ion Research (Sigurd Hofmann et al.).
7. Applications
Theoretical and experimental investigation of relativistic 6d⁹7s² vs 6d¹⁰7s¹ configuration inversion in Group 11
Detailed applications by field
- everyday
- Theoretical and experimental investigation of relativistic 6d⁹7s² vs 6d¹⁰7s¹ configuration inversion in Group 11
- industry
- Used in unknown properties processing, specialized alloys, and chemical manufacturing (Theoretical and experimental investigation of relativistic 6d⁹7s² vs 6d¹⁰7s¹ configuration inversion in Group 11).
- electronics
- Applied in electronic components, semiconductors, or functional coatings where Roentgenium's electronic structure ([Rn] 5f¹⁴ 6d⁹ 7s²) provides target conductivity.
- medicine
- Restricted to controlled nuclear medicine or fundamental radiochemical research.
- energy
- Utilized in power generation, battery materials, catalysts, or nuclear technology involving Roentgenium.
- aerospace
- High-performance materials, structural alloys, or space instrumentation utilizing Roentgenium.
- agriculture
- Not used in agriculture due to radioactivity or heavy-metal toxicity.
- science
- Spectroscopic standard, crystallography, and quantum chemistry studies of Period 7 d-block elements.
8. Biological role and safety
Hazard depends on the isotope, chemical form, dose and exposure route.
Elemental substances, ions, compounds and radioisotopes can have different health effects. This is an educational reference; laboratory work requires the material safety data sheet and trained supervision.
Biological role reference
Classified as highly radioactive / synthetic in human and biological systems.