105 · Db

Dubnium

Disputed claims from Dubna and Berkeley. The name dubnium adopted in 1997.

Identity

Atomic number: 105
Symbol: Db
Canonical name: Dubnium
Category: transition metal
Group: 5
Period: 7
Block: d

Bulk chemistry is not established. The table column is not a confirmed family.

Properties

These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.

Atomic mass: [268] No standard atomic weight. The number shown is the conventional mass number used in tables, not a measured mass in u.
Electron configuration: *[Rn] 5f14 6d3 7s2
Electrons per shell: 2, 8, 18, 32, 32, 11, 2
Standard state: not established
Density: 29.3 g/cm³ (estimated) Predicted value: the element has not been observed in bulk.

Notable isotopes

This summary is not an inventory of every isotope.

Conventional mass number: 268

History

Dubna claim

Synthesis · jointly credited · 1968

Dubna claims element 105. The evidence is disputed with Berkeley.

Berkeley claim

Synthesis · jointly credited · 1970

Berkeley announces its own synthesis. Official credit will be shared.

The name dubnium

Official recognition · officially recognized · 1997

IUPAC adopts the name dubnium in 1997.

See the element timeline

Etymology

Theme: place
Language: russe
Root: Dubna
Meaning: Dubna
Temporary systematic name: unnilpentium (Unp)
Official adoption: 1997

Scientists

Places and institutions

Dubna — historical setting : Soviet Union — present country : Russia
Berkeley — historical setting : United States — present country : United States