Ruthenium (Ru)

Ruthenium (Ru) is element 44, a transition metal. Atomic mass 101.07, configuration [Kr] 4d⁷ 5s¹ [exc]. Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.

Open Ruthenium in the interactive periodic table

Key facts

Atomic number44
SymbolRu
Standard atomic weight101.07(2)
CategoryTransition Metal
Group8
Period5
State at room temperatureSolid
Electron configuration[Kr] 4d⁷ 5s¹ [exc]
Valence electrons1 (Variable)
Common oxidation states+3, +4
Common ionsNo common ions
Electronegativity (Pauling)2.2
First ionization energy710 kJ/mol
Electron affinity101.3 kJ/mol
Atomic radius178 pm
Density12.1 g/cm³
Melting point2333°C
Boiling point4150°C
Specific heat0.238 J/(g·°C)

Natural isotopes

Common uses

Where it matters

Hazards

History

Discovered1844
Discovered byKarl Ernst Claus
NameFrom Ruthenia (Latin for Russia)