Last Updated: April 28, 2024


In the fascinating world of chemistry, there are elements that capture our imagination with their unique characteristics, and Ununennium is one such element. It stands out in the periodic table not because it’s found in nature, but because it is entirely man-made, a testament to human ingenuity in the field of science. Ununennium is part of an exclusive club known as superheavy elements, boasting an atomic number that places it in the realm of the unknown and uncharted. This element’s existence is fleeting, lasting only moments before it decays, yet its discovery and study offer invaluable insights into the boundaries of chemical science and the potential for new, yet-to-be-discovered elements. Ununennium’s presence enriches our understanding of chemistry, pushing the limits of what we know about the building blocks of the universe.

What Is Ununennium?

Ununennium, known by its periodic number 119, is a yet-to-be-discovered element anticipated to join the periodic table’s family of elements. It is predicted to be an alkali metal, placing it in the same group as familiar elements like sodium and potassium, which are known for their reactivity and metallic properties. The name “ununennium” is a temporary label, derived from its atomic number, awaiting the element’s official discovery and confirmation. Scientists worldwide are on the quest to synthesize ununennium by merging lighter atoms in high-energy experiments, hoping to unlock more about its properties and potential applications. This endeavor marks a significant step forward in the field of chemistry, pushing the boundaries of what we know about the natural world.

Ununennium Formula

  • Formula: Uue
  • Composition: Presumed to consist of one ununennium atom.
  • Bond Type: Predicted to form bonds with various degrees of covalency and ionicity, depending on the compounds it creates.
  • Molecular Structure: Expected to be monoatomic as a pure element, similar to other alkali metals.
  • Electron Configuration: Theoretical predictions suggest a highly complex outer shell structure due to relativistic effects.
  • Significance: Studying ununennium could unlock new aspects of quantum physics and chemistry, providing insights into the behavior of superheavy elements.
  • Role in Chemistry: As a member of the alkali metals, it’s anticipated to participate in reactions forming highly reactive and unstable compound.

Structure of Ununennium

The structure of Ununennium, an element with the periodic number 119, remains a topic of scientific speculation, as it has not yet been discovered or synthesized. Based on its position in the periodic table, ununennium is predicted to be the next alkali metal, following the properties and structure trends of its group members like lithium, sodium, and potassium. These elements are characterized by having a single electron in their outermost shell, making them highly reactive. Therefore, ununennium is expected to have a similar electronic configuration, with a single valence electron contributing to its chemical behavior and reactions.

Given its theoretical status, the detailed atomic structure, including the arrangement of electrons, protons, and neutrons, is yet to be defined through experimental observation and confirmation. The anticipation around ununennium’s structure and properties fuels ongoing research, as scientists worldwide aim to synthesize this element, shedding light on the unknown aspects of the periodic table’s eighth row. This endeavor not only advances our understanding of atomic theory but also paves the way for new materials and technologies.

Properties of Ununennium

Physical Properties of Ununennium

Here’s a table that outlines the theoretical physical properties of ununennium, drawing on trends observed in its group:

PropertyExpected Characteristics of Ununennium
State at Room TemperatureLikely to be a solid, based on the states of other alkali metals at room temperature.
ColorPredicted to be silvery-white or metallic, similar to other alkali metals.
DensityExpected to be higher than that of francium, the heaviest alkali metal currently known.
Melting PointAnticipated to have a low melting point, characteristic of alkali metals, but exact value is unknown.
Boiling PointLikely to have a relatively low boiling point, following the trend in its group, though the specific temperature is speculative.
Electrical ConductivityPredicted to be a good conductor of electricity, akin to other members of its group.
ReactivityHighly reactive, especially with water, as is typical for alkali metals. The exact reactivity level is yet to be determined.

Chemical Properties Of Ununennium

Reactivity with Water

When ununennium comes into contact with water, it is expected to react vigorously, producing ununennium hydroxide and hydrogen gas. This reaction can be represented as follows:

Uue + 2 H₂O → Uue(OH)₂ + H₂↑

This equation suggests an intense reaction, highlighting ununennium’s position as an extremely reactive element, even more so than cesium or francium, the current last known alkali metals.

Reactivity with Oxygen

Upon exposure to oxygen, ununennium is predicted to form an oxide. The reaction might be similar to that of other alkali metals with oxygen, potentially forming ununennium oxide (UueO₂), as demonstrated in the equation below:

4 Uue + O₂ → 2 UueO₂

This reaction emphasizes the alkali metal characteristic of forming oxides upon reacting with oxygen, although the exact stoichiometry might vary until experimentally confirmed.

Behavior in Halogen Reactions

Ununennium is expected to readily react with halogens to form various halides. For instance, its reaction with fluorine would likely produce ununennium fluoride (UueF), as shown in the following equation:

2 Uue + F₂ → 2 UueF

Similar reactions are anticipated with other halogens (chlorine, bromine, iodine), following the general trend of forming ionic bonds characteristic of alkali metals reacting with halogens.

Ionization Energy

While an equation does not directly represent ionization energy, it is a critical factor indicating ununennium’s reactivity. The low ionization energy of ununennium would make it easy for the element to lose its outermost electron, as suggested by its position in the periodic table, enhancing its reactivity in forming compounds.


Electronegativity does not have a direct chemical equation, but it significantly influences how ununennium would behave in chemical reactions. Its very low electronegativity would mean ununennium atoms have a minimal attraction for electrons in a chemical bond, making it likely to donate its electron in reactions and form positively charged ions (cations).

These equations and descriptions provide a theoretical insight into ununennium’s chemical behavior, underlining its expected position as a highly reactive alkali metal.

Thermodynamic Properties of Ununennium

Thermodynamic PropertyTheoretical Expectation for Ununennium
Standard StateSolid (assumed based on its group’s characteristics at room temperature)
Melting PointLikely low, following the trend of decreasing melting points in the group
Boiling PointExpected to be relatively low, consistent with alkali metals’ trends
Heat of FusionAnticipated to be moderate, as seen in other alkali metals, but unknown
Heat of VaporizationPredicted to follow the trend of alkali metals, yet remains speculative
Specific Heat CapacityLikely to be high, in line with the general properties of alkali metals
Thermal ConductivityExpected to be good, similar to other members of its group

Material Properties of Ununennium

Material PropertyExpected Characteristics for Ununennium
State at Room TemperaturePredicted to be solid, mirroring the physical state of other alkali metals.
HardnessLikely to be soft, as alkali metals are known for their low hardness.
Tensile StrengthExpected to have low tensile strength, consistent with the group’s properties.
DuctilityAnticipated to be ductile, allowing it to be stretched into thin wires.
MalleabilityLikely to be highly malleable, easily deformed under pressure without breaking.
Corrosion ResistanceExpected to be highly reactive and not resistant to corrosion, especially in the presence of water or air.
Thermal ExpansionPredicted to have a high thermal expansion rate, similar to other alkali metals.
Electrical ConductivityExpected to be an excellent conductor of electricity, following the trend of its group.

Electromagnetic Properties of Ununennium

PropertyExpected Characteristic
Electrical ConductivityAnticipated to be very high, as ununennium is expected to be a metal, allowing electrons to flow freely.
Magnetic SusceptibilityLikely to be paramagnetic or diamagnetic, similar to other alkali metals, depending on its electronic structure.
Ionization EnergyExpected to be low, facilitating the loss of its outer electron and enhancing its conductivity.
ElectronegativityPredicted to have very low electronegativity, indicating a weak ability to attract electrons in a bond.

Nuclear Properties of Ununennium

PropertyExpected Characteristic
Mass NumberPredicted to start around 295, considering the most stable isotopes of other superheavy elements.
StabilityLikely to have a short half-life, characteristic of superheavy elements, due to rapid radioactive decay.
Decay ModesExpected to undergo alpha decay or possibly spontaneous fission, similar to other heavy alkali metals.
Magic NumbersThough not a magic number itself, its pursuit involves reaching closer to theorized “island of stability” numbers.
Neutron CaptureMay exhibit slow or fast neutron capture, impacting its potential stability and synthesis process.

Preparation of Ununennium

Selection of Target and Projectile: Scientists would choose a heavy element, such as bismuth (Bi) or lead (Pb), as a target material. They would then select a lighter element, like calcium (Ca), as the projectile, due to its 20 protons adding up to ununennium’s 119 when combined with the target.

Acceleration: The projectile ions are accelerated to high speeds using a particle accelerator. This equipment boosts the ions to the necessary velocities for overcoming the repulsive forces between two nuclei.

Collision: The accelerated ions collide with the target material in a specially designed detector chamber. The energy and speed of these collisions must be precisely controlled to encourage the nuclei of the target and projectile atoms to fuse rather than shatter.

Detection of Synthesis: If fusion occurs, a new atom of ununennium would be formed momentarily before it decays. Special detectors track the radiation signatures of these decay events, indicating the creation of the new element.

Confirmation: The detection of specific decay patterns, unique to ununennium, would confirm its synthesis. Researchers would repeat the experiment to ensure reproducibility, a key criterion for official recognition by the scientific community.

Chemical Compounds of Ununennium

Ununennium Hydride (UueH)

Ununennium hydride is predicted to form when ununennium reacts with hydrogen, similar to other alkali metals forming hydrides. This compound would likely be highly reactive and unstable.

Equation: Uue + H₂ → UueH₂

Ununennium Oxide (UueO)

Ununennium oxide would be expected if ununennium reacts with oxygen. This compound might exhibit properties similar to the oxides of other alkali metals, possibly forming a basic oxide.

Equation: 4 Uue + O₂ → 2 UueO₂

Ununennium Fluoride (UueF)

This compound is anticipated to result from the reaction of ununennium with fluorine, forming a ununennium salt that is likely highly soluble in water.

Equation: Uue + F₂ → UueF₂

Ununennium Chloride (UueCl)

Ununennium chloride would form through the reaction of ununennium with chlorine. Like other alkali metal chlorides, it would be expected to be a highly reactive salt.

Equation: Uue + Cl₂ → UueCl₂

Ununennium Iodide (UueI)

This compound would likely result from ununennium’s reaction with iodine, forming a salt. It’s expected to share characteristics with other alkali metal iodides, being highly reactive.

Equation: Uue + I₂ → UueI₂

Isotopes of Ununennium

IsotopePredicted Half-lifeDecay Mode
Uue-295Very short (milliseconds to seconds)Alpha decay
Uue-296Very short (milliseconds to seconds)Alpha decay, possibly spontaneous fission
Uue-297Very short (milliseconds to seconds)Alpha decay
Uue-298Very short (milliseconds to seconds)Alpha decay, possibly spontaneous fission
Uue-299Very short (milliseconds to seconds)Alpha decay

Uses of Ununennium

Scientific Research

The primary use of ununennium, once synthesized, would be in scientific research. Its discovery would provide invaluable insights into the chemical and physical properties of superheavy elements, expanding our understanding of the periodic table and atomic theory.

Nuclear Physics

Ununennium’s isotopes might offer new pathways in nuclear physics, especially concerning the stability of superheavy elements. Studying its decay modes and half-lives could help scientists explore the theoretical “island of stability” in the superheavy element region.

Advanced Materials

Although highly speculative, compounds of ununennium could have unique properties that might find applications in creating new materials. These could be of interest in fields requiring extreme conditions, such as high-energy physics experiments.

Medical and Industrial Isotopes

If ununennium or its isotopes exhibit any unique radioactive properties, they might find niche applications in medicine or industry, similar to how other radioactive elements are used in cancer treatment or in radiographic equipment.


The discovery and study of ununennium would serve as a powerful educational tool, illustrating the complexities of chemical synthesis, the periodic law, and the limits of chemical knowledge, inspiring future generations of scientists.

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