Dubnium Element Facts

The chemical element dubnium is classed as a transition metal. It was discovered in 1970 by a team of scientists led by Georgy Flerov.

Dubnium is radioactive.
Dubnium Radioactive

Data Zone

Classification: Dubnium is a transition metal
Atomic weight: 268, no stable isotopes
State: solid (presumed)
Melting point:
Boiling point:
Electrons: 105
Protons: 105
Neutrons in most abundant isotope: 163
Electron shells: 2,8,18,32,32,11,2
Electron configuration: [Rn] 5f14 6d3 7s2
Density @ 20oC:
Show more, including: Heats, Energies, Oxidation, Reactions, Compounds, Radii, Conductivities
Atomic volume:
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:

The cyclotron at Dubna

Part of the heavy ion cyclotron U400 in Dubna, Russia. Image by Jim Roberto, Oak Ridge National Laboratory

Discovery of Dubnium

Credit for the discovery of dubnium is shared between teams of scientists at the Joint Institute for Nuclear Research at Dubna, Russia and scientists at Lawrence Berkeley National Laboratory, California.

In 1968, the team in Russia led by Georgy Flerov bombarded an americium-243 target with neon-22 ions and synthesized isotopes of element 105, identified as 260Db or 261Db. The experiment was repeated a year later using gradient thermochromatography for more precise identification of the isotopes formed. Synthesis of 260Db was confirmed in 1970.

The Dubna team proposed calling the new element neilsbohrium (Ns) after the Nobel Prize winning physicist Niels Bohr.

In 1970, the team in California led by Albert Ghiorsio also attempted to synthesize element 105. They had no success with repeating the Russian experiment but they successfully synthesized element 105 by bombarding a californium-249 target with nitrogen-15 ions.

They suggested the name hahnium (Ha) for the new element, after the Nobel Prize winning chemist Otto Hahn.

The Council of the International Union of Pure and Applied Chemistry (IUPAC) decided in 1997 that transactinide element 105 should be given the name Dubnium (Db) after the research facility in Russia where it was synthesized.

Appearance and Characteristics

Harmful effects:

Dubnium is harmful due to its radioactivity.


Dubnium is a transactinide or super-heavy element.

It is a radioactive synthetic metal and has only been produced in tiny amounts.

Uses of Dubnium

Dubnium is of research interest only.

Abundance and Isotopes

Abundance earth’s crust: nil

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

Cost, pure: $ per 100g

Cost, bulk: $ per 100g

Source: Dubnium is a synthetic radioactive metal, created by nuclear bombardment, and has only been produced in tiny amounts. Dubnium is made by bombarding californium-249 with nitrogen. It can also be produced by bombarding americium-243 with neon.

Isotopes: Dubnium has 12 isotopes whose half-lives are known, with mass numbers from 256 to 270. None are stable. The most stable isotope is 268Db, with a half-life of 32 hours.

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