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About Zirconium

Zirconium Bohr

Zirconium minerals are very common, and have been known to human civilizations for centuries, often used as precious stones. The first chemist to recognize that the mineral zircon contained a new “earth”--a term early chemists applied to metal oxides--distinct from the already well characterized alumina was Martin Heinrich Klaproth, and he named the new metallic element for its source mineral in 1789. The famous chemist Jons Jakob Berzelius was the first to actually isolate the metal in pure form, a feat accomplished in 1824.

The vast majority of zirconium used commercially is found as some form of zirconium dioxide, also known as zirconia. Zirconia can exhibit three different crystal structures depending on temperature. Unstabilized zirconia may crack when heated or cooled due to transitions between these phases, but stabilized cubic zirconia, produced via addition of oxides of other metals, generally magnesium, yttrium, calcium, or cerium, is extremely stable across wide temperature ranges. Stabilized zirconia is frequently used as a refractory ceramic material, in the form of lab crucibles, metal furnaces, thermal barrier coatings, and as a surface coating for foundry molds. It is useful for joining ceramic and metal surfaces, as it has similar thermal expansion properties to steel. Zirconia is also biocompatible, and is frequently used as as material for medical implants, either alone, as a coating for metal implants, or in composite metal-ceramic devices. Ytrrium stabilized zirconia is useful as an electroceramic, found in sensors for detecting conditions such as pH and oxygen levels, and when doped with rare earths can be used for phosphor thermometry. Zirconia is also notable for its ability to conduct ions, which lends it to use as a solid electrolyte in fuel cells.

Zirconium is also a component several other important ceramic materials. Zirconium carbide and zirconium nitride are extremely hard ceramics generally used as refractory materials or cutting tools. Additionally, zirconium is a component of some electroceramics, the most well known example being lead zirconate titanate, a material used frequently in ceramic capacitors, sensors, and actuators. This compound is essential for the production of ferroelectric RAM, a form of non-volatile random access memory being actively researched by several electronics manufacturers.

A few other zirconium compounds have niche applications as chemical agents. Ammonium and potassium zirconium carbonates are used in paper coatings used for the production of high-quality prints. Other zirconium compounds find use as crosslinkers in polymers or in inks to promote adhesion to metals and plastics. Additionally, zirconium hydrides are used as hydrogenation catalysts, reducing agents, foaming agents, and to help produce seals between metals and ceramics.

As a metal, zirconium is used as an alloying agent. Its primary advantage is high resistance to corrosion, which lends it to use in specialty alloys designed for use in highly corrosive environments. Additionally, zirconium is biocompatible, lending it to use in alloys for metal implants, and has a low absorption cross section for thermal neutrons, which dictates its use in nuclear fuel cladding.

Zircon, the source of all zirconium used commercially, is a silicate mineral found as a minor component of heavy mineral sands, which also contain the source minerals for titanium. The two elements are therefore co-products of the same mining operations. Most zircon is never converted to the pure element, and is instead converted to zirconium dioxide, which is the starting material for most other zirconium products. Zirconium metal is produced only for use in alloying applications, uses the Kroll process, which requires converting zircon to zirconium tetrachloride, which is then reduced to the metal using magnesium. Zircon is also used directly as an opacifier in decorative ceramics, and large crystals of sufficient quality are cut for use as gemstones.

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Zirconium is mainly used as a refractory and opacifier. Heating zirconia initiates a phase transformation process resulting in a solid solution. This solid solution is termed as stabilized zirconia, a valuable refractory. High Purity (99.999%) Zirconium (Zr) Sputtering TargetZirconium is used to a lesser extent as an alloying agent due to its strong resistance to corrosion. High Purity (99.999%) Zirconium Oxide (ZrO2) PowderZirconium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Zirconium nanoparticles and nanopowders provide ultra-high surface area. Zirconium oxides are available in numerous forms such as powder and dense pellets for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Zirconium is also available in soluble forms including zirconium chloride, nitrate and acetate. These compounds can be manufactured as solutions at specified stoichiometries.

Zirconium Properties

Zirconium(Zr) atomic and molecular weight, atomic number and elemental symbol Zirconium is a Block D, Group 4, Period 5 element. Zirconium Bohr ModelThe number of electrons in each of Zirconium's shells is 2, 8, 18, 10, 2 and its electron configuration is [Kr] 4d2 5s2. Elemental ZirconiumThe zirconium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-67-7, zirconium has a silvery white appearance. Zirconium’s principal mineral is zircon (zirconium silicate). Zirconium is produced as a byproduct of titanium and tin mining. It is not found in nature as a native metal. Zirconium was first isolated by Jons Jakob Berzelius in 1824. The name of zirconium comes from the mineral zircon, the most important source of zirconium, and from the Persian word 'zargun' meaning gold color or gold-like.

Symbol: Zr
Atomic Number: 40
Atomic Weight: 91.224
Element Category: transition metal
Group, Period, Block: 4, 5, d
Color:  silvery white/ grayish-white
Other Names: Zirkonium, Zirconio, Circonio
Melting Point: 1855 °C, 3371 °F, 2128 K
Boiling Point: 4409 °C, 7968 °F, 4682 K
Density: 6.52 g·cm3
Liquid Density @ Melting Point: 5.8 g·cm3
Density @ 20°C: 6.52 g/cm3
Density of Solid: 6511 kg·m3
Specific Heat: 0.0671 Cal/g/K @ 25 oC °C
Superconductivity Temperature: 0.61 [or -272.54 °C (-458.57 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 23
Heat of Vaporization (kJ·mol-1): 566.7
Heat of Atomization (kJ·mol-1): 607.47
Thermal Conductivity: 22.6 W·m-1·K-1
Thermal Expansion: (25 °C) 5.7 µm·m-1·K-1
Electrical Resistivity: (20 °C) 421 nΩ·m
Tensile Strength: 230 MPa
Molar Heat Capacity: 25.36 J·mol-1·K-1
Young's Modulus: 88 GPa
Shear Modulus: 33 GPa
Bulk Modulus: 91.1 GPa
Poisson Ratio: 0.34
Mohs Hardness: 5
Vickers Hardness: 903 MPa
Brinell Hardness: 650 MPa
Speed of Sound: (20 °C) 3800 m·s-1
Pauling Electronegativity: 1.33
Sanderson Electronegativity: 0.9
Allred Rochow Electronegativity: 1.22
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.67
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 40
Protons: 40
Neutrons: 51
Electron Configuration: [Kr] 4d2 5s2
Atomic Radius: 160 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 175±7 pm
Covalent Radius (Å): 1.48
Van der Waals Radius: 200 pm
Oxidation States: 4, 3, 2, 1 (amphoteric oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 41.088
1st Ionization Energy: 640.08 kJ·mol-1
2nd Ionization Energy: 1266.86 kJ·mol-1
3rd Ionization Energy: 2218.21 kJ·mol-1
CAS Number: 7440-67-7
EC Number: N/A
MDL Number: MFCD00011303
Beilstein Number: N/A
SMILES Identifier: [Zr]
InChI Identifier: InChI=1S/Zr
PubChem CID: 23995
ChemSpider ID: 22431
Earth - Total: 7.2 ppm
Mercury - Total: 5.5 ppm
Venus - Total: 7.5 ppm
Earth - Seawater (Oceans), ppb by weight: 0.026
Earth - Seawater (Oceans), ppb by atoms: 0.0018
Earth -  Crust (Crustal Rocks), ppb by weight: 130000
Earth -  Crust (Crustal Rocks), ppb by atoms: 30000
Sun - Total, ppb by weight: 40
Sun - Total, ppb by atoms: 0.5
Stream, ppb by weight: 3
Stream, ppb by atoms: 0.03
Meterorite (Carbonaceous), ppb by weight: 6700
Meterorite (Carbonaceous), ppb by atoms: 1600
Typical Human Body, ppb by weight: 50
Typical Human Body, ppb by atom: 3
Universe, ppb by weight: 50
Universe, ppb by atom: 0.7
Discovered By: Martin Heinrich Klaproth
Discovery Date: 1789
First Isolation: Jöns Jakob Berzelius (1824)

Health, Safety & Transportation Information for Zirconium

Zirconium is non-toxic, however, safety data for Zirconium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Zirconium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H250-H251-H260
Hazard Codes F
Risk Codes 15-17
Safety Precautions 43-7/8
RTECS Number ZH7070000
Transport Information UN 1358 4.1/PG 2
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)

Zirconium Isotopes

Zirconium has four stable isotopes: 90Zr, 91Zr, 92Zr and 94Zr.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
78Zr 77.95523(54)# 50# ms [>170 ns] Unknown 0+ N/A 627.18 -
79Zr 78.94916(43)# 56(30) ms ß+ + p to 78Sr; ß+ to 79Y 5/2+# N/A 640.85 -
80Zr 79.9404(16) 4.6(6) s ß+ to 80Y 0+ N/A 657.31 -
81Zr 80.93721(18) 5.5(4) s ß+ to 81Y; ß+ + p to 80Sr (3/2-)# N/A 668.19 -
82Zr 81.93109(24)# 32(5) s ß+ to 82Y 0+ N/A 681.85 -
83Zr 82.92865(10) 41.6(24) s ß+ to 83Y; ß+ + p to 82Sr (1/2-)# N/A 692.73 -
84Zr 83.92325(21)# 25.9(7) min ß+ to 84Y 0+ N/A 705.46 -
85Zr 84.92147(11) 7.86(4) min ß+ to 85Y 7/2+ N/A 715.41 -
86Zr 85.91647(3) 16.5(1) h EC to 86Y 0+ N/A 728.14 -
87Zr 86.914816(9) 1.68(1) h EC to 87Y (9/2)+ N/A 738.09 -
88Zr 87.910227(11) 83.4(3) d EC to 88Y 0+ N/A 749.89 -
89Zr 88.908890(4) 78.41(12) h EC to 89Y 9/2+ N/A 759.83 -
90Zr 89.9047044(25) STABLE - 0+ N/A 771.64 51.45
91Zr 90.9056458(25) STABLE - 5/2+ -1.30362 778.78 11.22
92Zr 91.9050408(25) STABLE - 0+ N/A 786.86 17.15
93Zr 92.9064760(25) 1.5 x 106 y ß- to 93Nb 5/2+ N/A 794.01 -
94Zr 93.9063152(26) Observationally Stable - 0+ N/A 802.09 17.38
95Zr 94.9080426(26) 64.032(6) d ß- to 95Nb 5/2+ N/A 808.3 -
96Zr 95.9082734(30) 3.9 x 1019 y - to 96Mo 0+ N/A 816.38 2.8
97Zr 96.9109531(30) 16.744(11) h ß- to 97Nb 1/2+ N/A 822.6 -
98Zr 97.912735(21) 30.7(4) s ß- to 98Nb 0+ N/A 828.81 -
99Zr 98.916512(22) 2.1(1) s ß- to 99Nb 1/2+ N/A 833.17 -
100Zr 99.91776(4) 7.1(4) s ß- to 100Nb 0+ N/A 840.31 -
101Zr 100.92114(3) 2.3(1) s ß- to 101Nb 3/2+ N/A 845.6 -
102Zr 101.92298(5) 2.9(2) s ß- to 102Nb 0+ N/A 853.68 -
103Zr 102.92660(12) 1.3(1) s ß- to 103Nb (5/2-) N/A 861.75 -
104Zr 103.92878(43)# 1.2(3) s ß- to 104Nb 0+ N/A 869.83 -
105Zr 104.93305(43)# 0.6(1) s ß- to 105Nb; ß- + n to 104Nb N/A N/A 868.6 -
106Zr 105.93591(54)# 200# ms [>300 ns] ß- to 106Nb 0+ N/A 876.67 -
107Zr 106.94075(32)# 150# ms [>300 ns] ß- to 107Nb N/A N/A 875.44 -
108Zr 107.94396(64)# 80# ms [>300 ns] ß- to 108Nb 0+ N/A 883.52 -
109Zr 108.94924(54)# 60# ms [>300 ns] Unknown N/A N/A 891.59 -
110Zr 109.95287(86)# 30# ms [>300 ns] Unknown 0+ N/A 890.36 -