Zr
Zirconium
Element 40 · Transition metal
Zirconium (Zr)
Zirconium is a strong, corrosion-resistant metal that barely absorbs neutrons, making it ideal for nuclear fuel cladding.
- Transition metal
- Period 5
- Group 4
- d-block
- solid at room temperature
Key properties
- Atomic mass
- 91.22
- u
- Electron configuration
- [Kr] 4d2 5s2
- Melting point
- 1,854.9 °C
- 2,128 K
- Boiling point
- 4,408.9 °C
- 4,682 K
- Density
- 6.52 g/cm³
- Electronegativity
- 1.33
- Pauling
- Atomic radius
- 186 pm
- van der Waals
- 1st ionisation energy
- 6.634 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about zirconium
- 01
Zircon crystals from Western Australia are about 4.4 billion years old — the oldest known pieces of Earth.
- 02
Cubic zirconia is a popular, inexpensive diamond substitute.
- 03
About 90% of zirconium metal is used in nuclear reactors.
Applications
What is zirconium used for?
- Nuclear fuel rod cladding
- Ceramics and refractories
- Cubic zirconia gems
- Dental crowns
History
Discovery & name origin
Discovered by
Year
Where
Germany
Name origin
Persian zargun, “gold-coloured”, from the gemstone zircon.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 40
- Atomic mass
- 91.22 u
- Group
- 4
- Period
- 5
- Block
- d-block
- Electron configuration
- [Kr] 4d2 5s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2
- Electrons per shell
- 2, 8, 18, 10, 2
- Electronegativity (Pauling)
- 1.33
- Electron affinity
- 0.426 eV
- Atomic radius (van der Waals)
- 186 pm
- Stable isotopes
- 4
Oxidation states
Highlighted: common oxidation states (+4).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st640.1
- 2nd1,270
- 3rd2,218
- 4th3,313
- 5th7,752
- 6th9,500
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 2,128 K · 1,854.9 °C · 3,370.7 °F
- Boiling point
- 4,682 K · 4,408.9 °C · 7,967.9 °F
- Density
- 6.52 g/cm³
- Molar heat capacity
- 25.36 J/(mol·K)
- Appearance
- Silvery white
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Zirconium questions
What is Zr on the periodic table?
Zr is the symbol for zirconium, element 40 on the periodic table. It sits in group 4, period 5, in the transition metal category, and has an atomic mass of 91.22.
What is the atomic number of zirconium?
Zirconium has atomic number 40, so every zirconium atom has 40 protons in its nucleus. Its symbol is Zr and its atomic mass is 91.22.
Who discovered zirconium?
Zirconium was discovered by Martin Heinrich Klaproth in 1789 (Germany). The name comes from Persian zargun, “gold-coloured”, from the gemstone zircon.
What is zirconium used for?
Zirconium is used for: nuclear fuel rod cladding; ceramics and refractories; cubic zirconia gems; dental crowns.
Is zirconium a metal?
Yes. Zirconium is a transition metal, one of the metallic elements.
What is the electron configuration of zirconium?
The electron configuration of zirconium is [Kr] 4d2 5s2. Its 40 electrons are arranged in shells as 2, 8, 18, 10, 2.