About

Ruthenium is a rare transition metal belonging to the platinum group, making it a noble metal. It is used as a hardener for platinum and palladium alloys, making them more wear-resistant for things like electrical contacts and fountain pen nibs. It is also a versatile catalyst, used in the chemical industry to produce ammonia and acetic acid. Research into its use in solar cells is ongoing.

Atomic Properties

Atomic Number44

Atomic Weight101.07 u

Neutrons (common)58

Electron Configuration[Kr] 4d⁷ 5s¹

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁷ 5s¹

Electrons per Shell2, 8, 18, 15, 1

Electronegativity2.2

Electron Affinity100.96 kJ/mol

Oxidation States+2, +3, +4, +6, +8

Covalent Radius126 pm

Ionic Radius62 pm

Periodic Table Position

Group8

Period5

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearancesilvery white metallic

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound5,970 m/s

Poisson Ratio0.3

Thermal Properties

Melting Point2,607 K

Boiling Point4,423 K

Thermal Expansion0 1/K

Thermal Conductivity117 W/(m·K)

Specific Heat0.238 J/(g·K)

Molar Heat24.06 J/(mol·K)

Heat of Fusion24 kJ/mol

Heat of Vaporization595 kJ/mol

Abundance

In Earth's Crust0.001 ppm

In Ocean0 ppm

In Solar System0.005 ppm

In Universe0.004 ppm

Discovery

Discovered byKarl Ernst Claus

Discovery Year1,844

Occurrenceprimordial

CAS Number7440-18-8

Electron Configuration

Energy

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Isotopes of Ruthenium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁹⁶Ru	95.907600	5.54%	Stable	Stable
⁹⁸Ru	97.905290	1.87%	Stable	Stable
⁹⁹Ru	98.905940	12.76%	Stable	Stable
¹⁰⁰Ru	99.904220	12.6%	Stable	Stable
¹⁰¹Ru	100.905580	17.06%	Stable	Stable
¹⁰²Ru	101.904350	31.55%	Stable	Stable
¹⁰⁴Ru	103.905430	18.62%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Ruthenium in our interactive viewer.

View 3D Model of Ruthenium