Ruthenium

Atomic number

44

Atomic mass (u)

101.1

Category

Transition metal

Standard state

Solid

Melting point

2333.85 °C (2607 K)

Boiling point

4149.85 °C (4423 K)

Density (g/cm³)

12.1

Electronegativity (Pauling)

2.2

Electron configuration

[Kr]5s1 4d7

Oxidation states

+3

Atomic radius (pm)

207

First ionization energy (eV)

7.361

Discovery & recognition

Discovery year / period (PubChem)

1827

Discovery credited to (RSC)

Karl Karlovich Klaus

Date or period recorded by RSC

1844

Discovery place

Kazan, Russia (confirmed identification)

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

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Ruthenium is one of the rarest metals on Earth.”

Royal Society of Chemistry · occurrence excerpt ↗

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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.