Roentgenium

Atomic number

111

Atomic mass (u)

282.169

Category

Transition metal

Standard state

Expected to be a Solid

Melting point

Not reported

Boiling point

Not reported

Density (g/cm³)

Not reported in this source

Electronegativity (Pauling)

Not reported in this source

Electron configuration

[Rn]7s2 5f14 6d9 (predicted)

Oxidation states

5, 3, 1, -1

Atomic radius (pm)

Not reported in this source

First ionization energy (eV)

Not reported in this source

Discovery & recognition

Discovery year / period (PubChem)

1994

Discovery credited to (RSC)

Peter Armbruster and Gottfried Münzenberg

Date or period recorded by RSC

1994

Discovery place

GSI, Germany

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

This transuranium element is primarily produced through nuclear reactions in reactors or particle accelerators. Some transuranium elements also occur naturally in extremely small traces; that is different from a mineable deposit.

“A man-made element of which only a few atoms have ever been created.”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.