Ununtrium Element Facts


Ununpentium will decay into ununtrium by emission of an alpha particle. Image: LLNL


Data Zone

Classification: Ununtrium is an ‘other metal’ (presumed)
Atomic weight: (286), no stable isotopes
State: solid (presumed)
Melting point:
Boiling point:
Electrons: 113
Protons: 113
Neutrons in most abundant isotope: 173
Electron shells: 2, 8, 18, 32, 32, 18, 3
Electron configuration: [Rn] 5f14 6d10 7s2 7p1
Show more, including: Heats, Energies, Oxidation, Reactions, Compounds, Radii, Conductivities
Specific heat capacity
Heat of fusion
Heat of atomization
Heat of vaporization
1st ionization energy
2nd ionization energy
3rd ionization energy
Electron affinity
Minimum oxidation number
Min. common oxidation no.
Maximum oxidation number
Max. common oxidation no.
Electronegativity (Pauling Scale)
Polarizability volume
Reaction with air
Reaction with 15 M HNO3
Reaction with 6 M HCl
Reaction with 6 M NaOH
Atomic radius
Ionic radius (1+ ion)
Ionic radius (2+ ion)
Ionic radius (3+ ion)
Ionic radius (1- ion)
Ionic radius (2- ion)
Ionic radius (3- ion)
Thermal conductivity
Electrical conductivity
Freezing/Melting point:

Element 115 decay

Heavy elements 113 and 115 may have been made after combining calcium-48 and amercium-243. Image: LLNL.

Ununtrium is radioactive.

Ununtrium is radioactive.

Discovery of Ununtrium

Dr. Doug Stewart

Research scientists at the Joint Institute for Nuclear Research in Dubna, Russia and the Lawrence Livermore National Laboratory (LLNL), California believed they had made element 113, ununtrium, in Dubna, Russia in 2003. The work was a collaboration between science teams led by Yuri Oganessian and Ken Moody.

The team gathered data indicating that element 113 had been made by alpha decay of element 115. Element 115 was synthesized by fusion of element 20 with element 95: calcium-48 with americium-243.

The experiment began on July 14, 2003, and ended on August 10, 2003. Calcium ions were formed into a beam in a cyclotron (a particle accelerator) and fired at a target layer of americium deposited on titanium foil. Four atoms of element 115 (ununpentium) may have been produced, which then decayed to element 113 (ununtrium). (1)

The researcher’s data indicates one atom of ununtrium-283 and three atoms of ununtrium-284 were made. (2)

In 2011, The International Union of Pure and Applied Chemistry (IUPAC) reviewed the work done in Dubna and at the LLNL, and did not accept the discovery of ununtrium.

The report stated, “the results are encouraging but do not meet the criteria for discovery because of the paucity of events, the lack of connections to known nuclides, and the absence of cross-bombardments.” (3)

As a result of its position in the periodic table, ununtrium would be expected to be classed as one of the “other metals” and to have similar properties to the metal thallium. Too little of the element has been synthesized for this to be confirmed.

The joint teams at JINR in Dubna and Lawrence Livermore in California have published evidence for the synthesis of elements 113, 114, 115, 116, 117 and 118.

IUPAC has accepted the discoveries of element 114 (ununquadium) and element 116 (ununhexium). It has not yet considered the evidence for the discovery of element 117 (ununseptium).

IUPAC requires stronger evidence before it will confirm the synthesis of element 113 (ununtrium), element 115 (ununpentium), or element 118 (ununoctium).

Appearance and Characteristics

Harmful effects:

Ununtrium is harmful due to its radioactivity.


Ununtrium is a synthetic radioactive metal.

Uses of Ununtrium

Ununtrium is of research interest only.

Abundance and Isotopes

Abundance earth’s crust: nil

Abundance solar system: parts per trillion by weight, parts per trillion by moles

Cost, pure: $ per 100g

Cost, bulk: $ per 100g

Source: Ununtrium could theoretically be produced by bombarding 243Am with 48Ca in a heavy ion accelerator. The element could theoretically also be created using a cold fusion reaction between bismuth and zinc ions. IUPAC does not accept there is enough evidence yet to accept ununtrium as an established element.

Isotopes: Ununtrium may have 6 isotopes whose half-lives are known, with mass numbers from 278 to 286. None are stable.


1. Lawrence Livermore National Laboratory, Livermore Scientists Team With Russia To Discover Elements 113 and 115.
2. Yuri Oganessian et al., Experiments on the Synthesis of Element 115., pdf download
3. Robert Barber, Paul Karol, Hiromichi Nakahara, Emanuele Vardaci, and Erich Vogt, Discovery of the elements with atomic numbers greater than or equal to 113,. 2011, IUPAC. (pdf download)

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