About

Dubnium is a synthetic element named after Dubna, Russia, home of the Joint Institute for Nuclear Research where it was first synthesized. It is extremely unstable, with its most stable isotope having a half-life of just over a day. Its chemical properties are difficult to determine but are predicted to be similar to tantalum. It has no practical uses outside of research.

Atomic Properties

Atomic Number105

Atomic Weight268 u

Neutrons (common)163

Electron Configuration[Rn] 5f¹⁴ 6d³ 7s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s²

Electrons per Shell2, 8, 18, 32, 32, 11, 2

Oxidation States+5, +4, +3

Covalent Radius149 pm

Ionic Radius76 pm

Periodic Table Position

Group5

Period7

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Crystal Structurebcc

Thermal Properties

Melting Point2,900 K

Boiling Point3,400 K

Discovery

Discovered byJoint Institute for Nuclear Research and Lawrence Berkeley National Laboratory

Discovery Year1,968

Occurrencesynthetic

CAS Number53850-35-4

Electron Configuration

Energy

↿⇂

1s

↿⇂

2s

↿⇂

2p

↿⇂

3s

↿⇂

3p

↿⇂

4s

↿⇂

3d

↿⇂

4p

↿⇂

5s

↿⇂

4d

↿⇂

5p

↿⇂

6s

↿⇂

4f

↿⇂

5d

↿⇂

6p

↿⇂

7s

↿⇂

5f

↿

6d

7p

Isotopes of Dubnium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁶⁸Db	268.125670	—	29 h	Spontaneous Fission, Alpha Decay