Ununennium (Uue)
SuperactinideStandard Atomic Weight
N/AElectron configuration
[Og] 8s¹Melting point
N/ABoiling point
N/ADensity
3 kg/m³Oxidation states
++1, ++3Electronegativity (Pauling)
0.86Ionization energy (1st)
463.1 eVDiscovery year
N/AAtomic radius
240 pmUnunennium is the temporary IUPAC name for element 119, an undiscovered superheavy element placed below francium in group 1. All of its properties are predicted. It is expected to have an outer 8s electron and broadly alkali-metal-like chemistry, but strong relativistic effects may make it less simple than a direct extrapolation from cesium or francium. No isotope has been confirmed.
This element has not been synthesized or experimentally confirmed. All listed physicochemical properties are calculated, extrapolated, or model-dependent.
No macroscopic sample of ununennium exists, so its appearance is unknown. It is usually predicted to be a metallic solid under ordinary conditions, but color, luster, density, melting point, and other bulk properties have not been measured.
Ununennium has no confirmed practical, industrial, medical, or commercial use. If produced, it would be made atom by atom for nuclear and chemical research, chiefly to test models of superheavy nuclei, decay chains, and relativistic effects in the heaviest group 1 element. Any chemical study would probably involve single atoms or very small numbers of atoms and short observation times.
No compound of ununennium has been synthesized or characterized. Calculations predict that the +1 oxidation state and the Uue⁺ ion would be the most accessible, as in lighter alkali metals. Representative species considered in theoretical work include ununennium fluoride (UueF), ununennium chloride (UueCl), and ununennium hydroxide (UueOH). Relativistic stabilization of the 8s electron may alter bond strengths and volatility relative to simple periodic trends.
The safety properties of ununennium are not experimentally known. Any atoms produced would be radioactive, and isotope-specific half-lives and decay modes would control the hazard. In practice, risks would arise mainly from accelerator operation, radioactive targets, recoil products, and decay radiation, not from chemical toxicity of a bulk element. No ordinary exposure scenario exists.
Ununennium has no confirmed natural occurrence and no known environmental cycle. Because no isotope has been observed, its environmental mobility, speciation, and ecological effects are unmeasured. If atoms were produced in a laboratory, their quantities would be far too small for environmental behavior to be studied directly, and rapid radioactive decay is expected to dominate their fate.
Ununennium has no commodity market, commercial supply chain, or recoverable source. Production, if achieved, would require a heavy-ion accelerator, an intense beam, and a rare heavy actinide target, followed by atom-at-a-time detection. The limiting factors are target availability, beam time, very low reaction probabilities, and short-lived products. Economic discussion is therefore about research capability rather than demand, substitution, or recycling.
No confirmed ununennium has been detected on Earth or in extraterrestrial material. Superheavy nuclei near this region may be formed transiently in extreme nucleosynthesis environments, but any such atoms are expected to decay rapidly unless an unusually long-lived isotope exists. The proposed island of stability remains a theoretical motivation for searches.
- Ununennium is a systematic temporary name meaning one-one-nine.
- It would begin the eighth period of the periodic table if confirmed.
- No isotope of ununennium has yet been accepted as discovered.
- Its chemistry is inferred from theory and periodic trends, not experiments.
- Detection would rely on nuclear decay signatures rather than a visible sample.
- Relativistic effects are expected to be important for its 8s electron.
Images
Properties
Physical
- Atomic radius (empirical)
- 240 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 272 pm Compare Covalent radius of all elements →
- Density
- 3 kg/m³ Compare Density of all elements →
- Crystal structure
- Body-centered cubic Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 0.86 Compare Electronegativity (Pauling) of all elements →
- Electron affinity
- 0.25 eV
- Ionization energy (1st)
- 463.1 eV Compare Ionization energy (1st) of all elements →
- Oxidation states
- ++1, ++3 Compare Oxidation states of all elements →
- Electron configuration
- [Og] 8s¹
Thermodynamic
N/A
Nuclear
- Protons
- 119 Compare Protons of all elements →
- Known isotopes
- 0 Compare Known isotopes of all elements →
- Stable isotopes
- 0 Compare Stable isotopes of all elements →
- Natural occurrence
- Not observed
Abundance
N/A
Safety
- Radioactive
- Yes
Crystal Structure
N/A
Electronic Structure
- Electrons per shell
- 2, 8, 18, 32, 32, 18, 8, 1 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 54846-86-5 Compare CAS number of all elements →
Electron Configuration Predicted
——Electron configuration data not available for this ion.
Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
N/A
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
No stable isotopes.
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|
Phase / State
Phase/state data not available
N/A
Phase/state data not available