Dubnium

At a glance

Symbol

Db

Atomic number

105

Mass number of its longest-lived isotope

[268]

Group

5

Period

7

Family

transition metal

Electron configuration

[Rn] 5f¹⁴ 6d³ 7s² (predicted)

Electronegativity

not measured

Common ions

predicted +5, like tantalum

On the table

Period 7, group 5. The other transition metals are tinted, and every cell opens its own article.

Electrons and bonding

Only a handful of atoms have ever been made, each lasting seconds or less, so its chemistry is predicted from its place in the table rather than measured.

Properties

State at 25 °C

not known

Physical properties

none measured; no more than a few atoms have ever existed at once

Where it is found

Not found in nature. It is made a few atoms at a time in particle accelerators by fusing lighter nuclei, and each atom decays within seconds to hours.

Discovery and name

Georgy Flerov's team at Dubna reported it in 1968, and Albert Ghiorso's team at Berkeley reported it in 1970 and proposed the name hahnium. IUPAC gave shared credit and in 1997 named it dubnium, after the town that is home to the Joint Institute for Nuclear Research.