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What is Dubnium

Dubnium (pronounced as DUB-nee-em) belongs to the family of transition metals and denoted by the chemical symbol Db. It has 12 isotopes out of which the most stable one is dubnium-268 with a half-life of 32 hours [1, 2, 3].


Origin of its Name: It is named after Dubna, a town in Russia [1].

Who Discovered it: The name of its original discoverer is still under debate [1].

When and How was Dubnium Discovered

In 1968, Flerov and his team at the Joint Insitute for Nuclear Research (JINR) in Russia produced an isotope of the new element by bombarding americium with neon. Again in 1970, californium was targeted against neon by Ghiorso and his team at the American Lawrence Berkeley Laboratory (LBL) to synthesize isotope-261 of the element. They also challenged the claim of Flerov. While the Russian scientists called it neilsbohrium, the Americans gave the name hahnium.

Finally, it was named dubnium by the International Union of Pure and Applied Chemistry (IUPAC) [1].


Classification and Position of the Element on the Periodic Table [1]

Group 5
Period 7
Block d

Properties and Characteristics of Dubnium [1, 2, 3, 6]


General Properties

Relative atomic mass 268
Atomic mass 268 atomic mass units

Physical Properties

Color/appearance Unknown
Odor Unknown
Melting Point/freezing point Unknown
Boiling point Unknown
Density Unknown
State of matter at normal room temperature (Solid/Liquid/Gas) Solid (not confirmed)
Hardness Unknown

Chemical Properties

Flammability Unknown
Oxidation number Unknown

Atomic Data of Dubnium [1, 2, 3]

Atomic number 105
Valence electrons 5
Quantum numbers Unknown
– n 6
– ℓ 2
– m 0
– m s +1/2
Electron configuration (noble gas configuration) [Rn] 5f146d37s2
Atomic structure
– Number of electrons 105
– Number of neutrons 163
– Number of protons 105
Energy levels
– First energy level 2
– Second energy level 8
– Third energy level 18
– Fourth energy level 32
– Fifth energy level 32
– Sixth energy level 11
– Seventh energy level 2
Radius of atom
– Atomic radius Unknown
– Covalent radius 1.49 Å

Uses of Dubnium

As dubnium is neither found free in the environment nor produced in higher amounts at the laboratory, it has no applications other than basic scientific studies [1].

Dubnium Element

Interesting Facts

  • IUPAC had given the temporary name Unnilpentium to dubnium until the dispute regarding its original discovery was resolved [4].
  • It is a super-heavy element that might have properties similar to tantalum [5].

Dubnium Cost

The limited production of the radioactive metal in the laboratory does not make it commercially available.



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