ElementsWhat is dubnium?
Dubnium is a radioactive element made in particle accelerators, a few atoms at a time.
What is dubnium used for?
Research only.
Where the name comes from
From Dubna, the town in Russia that is home to the Joint Institute for Nuclear Research.
Key facts
- Symbol
- Db
- Atomic number
- 105
- Atomic mass
- 268.126 u
- Family
- Transition metal
- Period
- 7
- Group
- 5
- Block
- d
- State at room temperature
- Solid
- Melting point
- not measured
- Boiling point
- not measured
- Density
- not measured
- Electrons per shell
- 2, 8, 18, 32, 32, 11, 2
- Electron configuration
- [Rn]7s2 5f14 6d3
- Common oxidation states
- 5, 4, 3
- Electronegativity (Pauling)
- no value
- First ionisation energy
- not measured
- Electron affinity
- no value
- Atomic radius (van der Waals)
- no value
- Discovered
- 1967
Place in the periodic table
Dubnium is element number 105. It sits in period 7 (row 7) of the periodic table, in group 5 (column 5), and belongs to the d-block. Just before it comes rutherfordium (104), and just after it comes seaborgium (106). In the same column, tantalum is above it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature dubnium is a solid.
Inside the atom
An atom of dubnium has 105 protons in its nucleus and, when neutral, 105 electrons around it. The electrons are arranged in 7 shells: 2, 8, 18, 32, 32, 11, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Rn]7s2 5f14 6d3.
One mole of dubnium weighs 268.126 grams, so a single gram contains about 2.25 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains dubnium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.