Dubnium

1 · Identity

Symbol, number

Db, 105

Oxidation states in water

5, 4 and 3 (book entry); never measured in water

Note

Identity from the book entry; nothing measured in water.

Sources

Identity

Name and symbol

Dubnium, Db

Atomic number

105 protons

Position

group 5 · period 7 · d-block · transition metal

CAS number

53850-35-4

Atomic structure

Atomic mass

268 u

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d³
[Rn] 7s²⁵f¹⁴⁶d³

Electrons per shell

2, 8, 18, 32, 32, 11, 2

Valence electrons

5 ns and (n-1)d

Physical properties

State at room temperature

Solid

Melting point

not in sources

Boiling point

not in sources

Density

not in sources

Appearance

not in sources

Thermal conductivity

not in sources

Electrical resistivity

not in sources

Electrical conductivity

not in sources

Crystal structure

body-centered cubic

Molar heat capacity

not in sources

Chemical properties

Oxidation states

5, (4), (3) ​(parenthesized oxidation states are predictions)

Electronegativity

not in sources

Ionisation energy

6.8 eV

Electron affinity

not in sources

Atomic radius

not in sources

Ionic radius

not in sources

Reactivity

A group 5 transactinide known only from tracer experiments on single atoms; aqueous studies confirm a dominant +5 state like niobium and tantalum, with complexing behavior closer to niobium and protactinium than to tantalum.

with water

Not known; no experiment with water alone is reported.

with oxygen, air

Not known; gas-phase runs with traces of oxygen gave a less volatile species assigned to the oxybromide DbOBr3, and oxychlorides less volatile than the chlorides.

with acids

Single atoms in concentrated hydrochloric or hydrofluoric acid form anionic Db(V) halide complexes, probably DbOX4^- or Db(OH)2X4^-, which sorb on glass like the group 5 elements and extract like niobium rather than tantalum.

with halogens

Gas-phase experiments with bromine and chlorine gave volatile dubnium bromide and chloride, the bromide less volatile than niobium bromide and about as volatile as hafnium bromide.

Typical compounds

not in sources

Occurrence, production and use

Crustal abundance

Not Applicable

Oceanic abundance

Not Applicable

Occurrence and sources

• synthetic only californium-249 bombarded with nitrogen-15 nuclei

Extraction, production

not in sources

Uses

Due to the small amounts produced and its short half-life, there are currently no uses for dubnium outside of basic scientific research.

Safety, toxicity

not in sources

Discovery and name

Discovered by

independently by the Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research

Discovered

1970

First isolated

not in sources

Named by

not in sources

Origin of the name

after Dubna, Moscow Oblast, Russia, site of Joint Institute for Nuclear Research

Dubnium does not occur naturally in the Earth’s crust. Credit for the first synthesis of this element is given jointly to Albert Ghiorso and his team at the University of California in Berkeley and Georgi Flerov and his team at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia (Fig. IUPAC.105.1). The element is named for the location of the Joint Institute for Nuclear Research (JINR) laboratory in Dubna, Russia [646], [647]. Dubnium has no isotopic applications outside of scientific research.

Dubnium is named after the site of the Joint Institute for Nuclear Research in Dubna, Russia.