Bohrium

Named after Niels Bohr, whose model of the atom arranged electrons in shells.

At a glance

Symbol: Bh
Atomic number: 107
Mass number of its longest-lived isotope: [270]
Group: 7
Period: 7
Family: transition metal
Electron configuration: [Rn] 5f¹⁴ 6d⁵ 7s² (predicted)
Electronegativity: not measured
Common ions: predicted +7, like rhenium

On the table

Period 7, group 7. 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

Peter Armbruster and Gottfried Münzenberg's team at the GSI laboratory in Darmstadt, Germany, made it in 1981 by fusing chromium and bismuth nuclei. It was named after the Danish physicist Niels Bohr.

What it is used for

Research only. Experiments with a handful of atoms showed it forms an oxychloride, as rhenium above it does.