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Zirconium (Zr)

Zirconium is a chemical element of the periodic table with chemical symbol Zr and atomic number 40 with an atomic weight of 91.2242 u and is classed as transition metal and is part of group 4 (titanium group). Zirconium is solid at room temperature.

Zirconium in the periodic table

Atomic number40
Group4 (Titanium group)
ClassificationTransition Metal
AppearanceSilvery white
Color Silver
Number of protons40 p+
Number of neutrons51 n0
Number of electrons40 e-
From Wikipedia, the free encyclopediaZirconium is a chemical element with symbol Zr and atomic number 40. The name of zirconium is taken from the name of the mineral zircon, the most important source of zirconium. The word zircon comes from the Persian word zargun زرگون, meaning "gold-colored".

Physical properties

Phase at STPSolid
Density6.52 g/cm3
Atomic weight91.2242 u

Thermal properties

Melting point2128 K
1854.85 °C
3370.73 °F
Boiling point4650 K
4376.85 °C
7910.33 °F
Heat of vaporization590.5 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.33
Electron affinity41.806 kJ/mol
Oxidation states−2, 0, +1, +2, +3, +4
(an amphoteric oxide)
Ionization energies
  1. 640.1 kJ/mol
  2. 1270 kJ/mol
  3. 2218 kJ/mol
  4. 3313 kJ/mol
  5. 7752 kJ/mol
  6. 9500 kJ/mol

Electron configuration for zirconium

Electron configuration
Shorthand configuration
[Kr] 4d2 5s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d2 5s2
Electron configuration chart
Electrons per shell2, 8, 18, 10, 2
Valence electrons 4
Valency electrons 4
Bohr model
ZirconiumElectron shell for Zirconium, created by Injosoft ABZr
Figure: Shell diagram of Zirconium (Zr) atom.
Orbital Diagram

The history of Zirconium

DiscoveryMartin Heinrich Klaproth (1789)
First isolationJöns Jakob Berzelius (1824)
Discovery of zirconium
The zirconium-containing mineral zircon and related minerals (jargoon, hyacinth, jacinth, ligure) were mentioned in biblical writings. The mineral was not known to contain a new element until 1789, when Klaproth analyzed a jargoon from the island of Ceylon (now Sri Lanka). He named the new element Zirkonerde (zirconia). Humphry Davy attempted to isolate this new element in 1808 through electrolysis, but failed. Zirconium metal was first obtained in an impure form in 1824 by Berzelius by heating a mixture of potassium and potassium zirconium fluoride in an iron tube.The crystal bar process (also known as the Iodide Process), discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925, was the first industrial process for the commercial production of metallic zirconium.


List of unique identifiers for Zirconium in various chemical registry databases
CAS Number7440-67-7
ChemSpider ID22431
EC number231-176-9
PubChem CID Number23995