About

Rhodium is a silvery-white, hard, and corrosion-resistant noble metal. It is one of the rarest and most valuable precious metals, often more expensive than gold. Its main use, accounting for the vast majority of demand, is as a catalyst in the catalytic converters of automobiles to reduce harmful nitrogen oxide emissions from exhaust. It is also used to plate jewelry.

Atomic Properties

Atomic Number45

Atomic Weight102.906 u

Neutrons (common)58

Electron Configuration[Kr] 4d⁸ 5s¹

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁸ 5s¹

Electrons per Shell2, 8, 18, 16, 1

Electronegativity2.28

Electron Affinity110.27 kJ/mol

Oxidation States+1, +2, +3, +4

Covalent Radius135 pm

Ionic Radius66.5 pm

Periodic Table Position

Group9

Period5

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearancesilvery-white metallic

Crystal Structurefcc

Magnetic Orderingparamagnetic

Speed of Sound4,700 m/s

Poisson Ratio0.26

Thermal Properties

Melting Point2,237 K

Boiling Point3,968 K

Thermal Expansion0 1/K

Thermal Conductivity150 W/(m·K)

Specific Heat0.243 J/(g·K)

Molar Heat25.01 J/(mol·K)

Heat of Fusion21.5 kJ/mol

Heat of Vaporization494 kJ/mol

Abundance

In Earth's Crust0.001 ppm

In Ocean0 ppm

In Solar System0.001 ppm

In Universe0.001 ppm

Discovery

Discovered byWilliam Hyde Wollaston

Discovery Year1,803

Occurrenceprimordial

CAS Number7440-16-6

Electron Configuration

Energy

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Isotopes of Rhodium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁰³Rh	102.905500	100%	Stable	Stable

Interactive Visualization

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

View 3D Model of Rhodium