About

Zirconium is a lustrous, grayish-white transition metal that is highly resistant to corrosion from acids and alkalis. Because it does not readily absorb neutrons, it is widely used in nuclear reactors as cladding for fuel rods. Its oxide, zirconia, is used in hard ceramics, and a synthetic crystalline form is the popular diamond substitute, cubic zirconia.

Atomic Properties

Atomic Number40

Atomic Weight91.224 u

Neutrons (common)51

Electron Configuration[Kr] 4d² 5s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d² 5s²

Electrons per Shell2, 8, 18, 10, 2

Electronegativity1.33

Electron Affinity41.806 kJ/mol

Oxidation States+4

Covalent Radius148 pm

Ionic Radius72 pm

Periodic Table Position

Group4

Period5

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearancelustrous, grayish-white solid

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound3,800 m/s

Poisson Ratio0.34

Thermal Properties

Melting Point2,128 K

Boiling Point4,650 K

Triple Point2,128 K

Thermal Expansion0 1/K

Thermal Conductivity22.6 W/(m·K)

Specific Heat0.278 J/(g·K)

Molar Heat25.36 J/(mol·K)

Heat of Fusion14 kJ/mol

Heat of Vaporization591.6 kJ/mol

Abundance

In Earth's Crust165 ppm

In Ocean0 ppm

In Solar System0.009 ppm

In Human Body0.014 ppm

In Universe0.05 ppm

Discovery

Discovered byMartin Heinrich Klaproth

Discovery Year1,789

Occurrenceprimordial

CAS Number7440-67-7

Electron Configuration

Energy

↿⇂

↿

Isotopes of Zirconium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁹⁰Zr	89.904700	51.45%	Stable	Stable
⁹¹Zr	90.905640	11.22%	Stable	Stable
⁹²Zr	91.905040	17.15%	Stable	Stable
⁹³Zr	92.906470	—	1.61 My	Beta Minus Decay
⁹⁴Zr	93.906310	17.38%	Stable	Stable
⁹⁵Zr	94.908043	—	64.032 d	Beta Minus Decay
⁹⁶Zr	95.908270	2.8%	23.4 Ey	Double Beta Minus Decay

Interactive Visualization

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

View 3D Model of Zirconium