Zirconium
![]() | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Zirconium | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Pronunciation | /zɜːrˈkoʊniəm/ | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Appearance | silvery white | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Standard atomic weight Ar°(Zr) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Zirconium in the periodic table | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Heat of vaporization | 591 kJ/mol | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Molar heat capacity | 25.36 J/(mol·K) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Vapor pressure
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Atomic properties | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Oxidation states | common: +4 −2, Jöns Jakob Berzelius (1824) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Isotopes of zirconium | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Zirconium is a
Zirconium forms a variety of
Zirconium compounds have no known biological role, though the element is widely distributed in nature and appears in small quantities in biological systems without adverse effects. There is no indication of zirconium as a carcinogen. The main hazards posed by zirconium are flammability in powder form and irritation of the eyes.
Characteristics

Zirconium is a
The
At room temperature zirconium exhibits a hexagonally close-packed crystal structure, α-Zr, which changes to β-Zr, a body-centered cubic crystal structure, at 863 °C. Zirconium exists in the β-phase until the melting point.[16]
Isotopes
Naturally occurring zirconium is composed of five isotopes. 90Zr, 91Zr, 92Zr and 94Zr are stable, although 94Zr is predicted to undergo double beta decay (not observed experimentally) with a half-life of more than 1.10×1017 years. 96Zr has a half-life of 2.34×1019 years, and is the longest-lived radioisotope of zirconium. Of these natural isotopes, 90Zr is the most common, making up 51.45% of all zirconium. 96Zr is the least common, comprising only 2.80% of zirconium.[10]
Thirty-three artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 77 to 114.
Thirteen isotopes of zirconium also exist as metastable isomers: 83m1Zr, 83m2Zr, 85mZr, 87mZr, 88mZr, 89mZr, 90m1Zr, 90m2Zr, 91mZr, 97mZr, 98mZr, 99mZr, and 108mZr. Of these, 97mZr has the shortest half-life at 104.8 nanoseconds. 89mZr is the longest lived with a half-life of 4.161 minutes.[10]
Occurrence

Zirconium has a concentration of about 130 mg/kg within the
Zirconium is relatively abundant in S-type stars, and has been detected in the sun and in meteorites. Lunar rock samples brought back from several Apollo missions to the moon have a high zirconium oxide content relative to terrestrial rocks.[23]
Production
Occurrence
Zirconium is a by-product formed after mining and processing of the titanium minerals ilmenite and rutile, as well as tin mining.[25] From 2003 to 2007, while prices for the mineral zircon steadily increased from $360 to $840 per tonne, the price for unwrought zirconium metal decreased from $39,900 to $22,700 per ton. Zirconium metal is much more expensive than zircon because the reduction processes are costly.[21]
Collected from coastal waters, zircon-bearing sand is purified by spiral concentrators to separate lighter materials, which are then returned to the water because they are natural components of beach sand. Using magnetic separation, the titanium ores ilmenite and rutile are removed.[26]
Most zircon is used directly in commercial applications, but a small percentage is converted to the metal. Most Zr metal is produced by the reduction of the zirconium(IV) chloride with magnesium metal in the Kroll process.[13] The resulting metal is sintered until sufficiently ductile for metalworking.[19]
Separation of zirconium and hafnium
Commercial zirconium metal typically contains 1–3% of
Vacuum arc melting, combined with the use of hot extruding techniques and supercooled copper hearths, is capable of producing zirconium that has been purified of oxygen, nitrogen, and carbon.[33]
Hafnium must be removed from zirconium for nuclear applications because hafnium has a neutron absorption cross-section 600 times greater than zirconium.
Compounds
Like other transition metals, zirconium forms a wide range of inorganic compounds and coordination complexes.[36] In general, these compounds are colourless diamagnetic solids wherein zirconium has the oxidation state +4. Some organometallic compounds are considered to have Zr(II) oxidation state.[7] Non-equilibrium oxidation states between 0 and 4 have been detected during zirconium oxidation.[8]
Oxides, nitrides, and carbides
The most common oxide is
Zirconium tungstate has the unusual property of shrinking in all dimensions when heated, whereas most other substances expand when heated.[13] Zirconyl chloride is one of the few water-soluble zirconium complexes, with the formula [Zr4(OH)12(H2O)16]Cl8.[36]
Zirconium carbide and zirconium nitride are refractory solids. Both are highly corrosion-resistant and find uses in high-temperature resistant coatings and cutting tools.[40] Zirconium hydride phases are known to form when zirconium alloys are exposed to large quantities of hydrogen over time; due to the brittleness of zirconium hydrides relative to zirconium alloys, the mitigation of zirconium hydride formation was highly studied during the development of the first commercial nuclear reactors, in which zirconium carbide was a frequently used material.[41]
Lead zirconate titanate (PZT) is the most commonly used piezoelectric material, being used as transducers and actuators in medical and microelectromechanical systems applications.[42]
Halides and pseudohalides
All four common halides are known,
Fusion of the tetrahalides with additional metal gives lower zirconium halides (e.g. ZrCl3). These adopt a layered structure, conducting within the layers but not perpendicular thereto.[44]
The corresponding tetraalkoxides are also known. Unlike the halides, the alkoxides dissolve in nonpolar solvents. Dihydrogen hexafluorozirconate is used in the metal finishing industry as an etching agent to promote paint adhesion.[45]
Organic derivatives
Many complexes of Zr(II) are derivatives of zirconocene,[43] one example being (C5Me5)2Zr(CO)2.
History
The zirconium-containing mineral zircon and related minerals (
The
- ZrCl4 + 2 Mg → Zr + 2 MgCl2
Applications
Approximately 900,000 tonnes of zirconium ores were mined in 1995, mostly as zircon.[27]
Most zircon is used directly in high-temperature applications. Because it is refractory, hard, and resistant to chemical attack, zircon finds many applications. Its main use is as an opacifier, conferring a white, opaque appearance to ceramic materials. Because of its chemical resistance, zircon is also used in aggressive environments, such as moulds for molten metals.[27]
A small fraction of the zircon is converted to the metal, which finds various niche applications. Because of zirconium's excellent resistance to corrosion, it is often used as an alloying agent in materials that are exposed to aggressive environments, such as surgical appliances, light filaments, and watch cases. The high reactivity of zirconium with oxygen at high temperatures is exploited in some specialised applications such as explosive primers and as getters in vacuum tubes.[53] Zirconium powder is used as a degassing agent in electron tubes, while zirconium wire and sheets are utilized for grid and anode supports.[54][55] Burning zirconium was used as a light source in some photographic flashbulbs. Zirconium powder with a mesh size from 10 to 80 is occasionally used in pyrotechnic compositions to generate sparks. The high reactivity of zirconium leads to bright white sparks.[56]
Nuclear applications
Cladding for nuclear reactor fuels consumes about 1% of the zirconium supply,
One disadvantage of zirconium alloys is the reactivity with water, producing hydrogen, leading to degradation of the fuel rod cladding:[57]
- Zr + 2 H2O → ZrO2 + 2 H2
Hydrolysis is very slow below 100 °C, but rapid at temperature above 900 °C. Most metals undergo similar reactions. The redox reaction is relevant to the instability of
Zirconium is a constituent of uranium zirconium hydrides, nuclear fuels used in research reactors.[60]
Space and aeronautic industries
Materials fabricated from zirconium metal and ZrO2 are used in space vehicles where resistance to heat is needed.[28]
High temperature parts such as combustors, blades, and vanes in
Zirconium is also used as a material of first choice for
Medical uses
Zirconium-bearing compounds are used in many biomedical applications, including dental implants and
Zirconium binds urea, a property that has been utilized extensively to the benefit of patients with chronic kidney disease.[64] For example, zirconium is a primary component of the sorbent column dependent dialysate regeneration and recirculation system known as the REDY system, which was first introduced in 1973. More than 2,000,000 dialysis treatments have been performed using the sorbent column in the REDY system.[65] Although the REDY system was superseded in the 1990s by less expensive alternatives, new sorbent-based dialysis systems are being evaluated and approved by the U.S. Food and Drug Administration (FDA). Renal Solutions developed the DIALISORB technology, a portable, low water dialysis system. Also, developmental versions of a Wearable Artificial Kidney have incorporated sorbent-based technologies.[66]
Mixtures of monomeric and polymeric Zr4+ and Al3+ complexes with
Defunct applications
Zirconium carbonate (3ZrO2·CO2·H2O) was used in lotions to treat poison ivy but was discontinued because it occasionally caused skin reactions.[12]
Safety
Hazards | |
---|---|
NFPA 704 (fire diamond) |
Although zirconium has no known biological role, the human body contains, on average, 250 milligrams of zirconium, and daily intake is approximately 4.15 milligrams (3.5 milligrams from food and 0.65 milligrams from water), depending on dietary habits.
Short-term exposure to zirconium powder can cause irritation, but only contact with the eyes requires medical attention.
Among the numerous radioactive isotopes of zirconium, 93Zr is among the most common. It is released as a product of nuclear fission of 235U and 239Pu, mainly in nuclear power plants and during nuclear weapons tests in the 1950s and 1960s. It has a very long half-life (1.53 million years), its decay emits only low energy radiations, and it is not considered particularly hazardous.[75]
See also
- Zirconium alloys
- Zirconia light
Notes
- ^ The thermal expansion of a zirconium crystal is anisotropic: the parameters (at 20 °C) for each crystal axis are αa = 4.91×10−6/K, αc = 7.26×10−6/K, and αaverage = αV/3 = 5.69×10−6/K.[3]
References
- ^ "Standard Atomic Weights: Zirconium". CIAAW. 2024.
- ISSN 1365-3075.
- ^ ISBN 978-1-62708-155-9.
- .
- ISBN 9780080450476.
- ^ ISBN 978-0-08-037941-8.
- ^ .
- ^ ISSN 0003-6951.
- ISBN 0-8493-0486-5.
- ^ .
- ^ Online Etymology Dictionary.
- ^ ISBN 978-0-19-850341-5.
- ^ ISBN 978-0-8493-0488-0.
- ISBN 978-0-471-61525-5.
- ^ Winter, Mark (2007). "Electronegativity (Pauling)". University of Sheffield. Retrieved 2024-07-27.
- S2CID 56557217.
- S2CID 234019083.
- ^ a b Peterson, John; MacDonell, Margaret (2007). "Zirconium". Radiological and Chemical Fact Sheets to Support Health Risk Analyses for Contaminated Areas (PDF). Argonne National Laboratory. pp. 64–65. Archived from the original (PDF) on 2008-05-28. Retrieved 2008-02-26.
- ^ a b c d "Zirconium". How Products Are Made. Advameg Inc. 2007. Retrieved 2008-03-26.
- ^ "Zirconium and Hafnium – Mineral resources" (PDF). 2014.
- ^ a b "Zirconium and Hafnium" (PDF). Mineral Commodity Summaries: 192–193. January 2008. Retrieved 2008-02-24.
- ^ Ralph, Jolyon & Ralph, Ida (2008). "Minerals that include Zr". Mindat.org. Retrieved 2008-02-23.
- ISSN 0028-0836.
- ISSN 0021-9606.
- ^ Callaghan, R. (2008-02-21). "Zirconium and Hafnium Statistics and Information". US Geological Survey. Retrieved 2008-02-24.
- ISBN 81-87053-53-4.
- ^
- ^ ISBN 978-0-19-508083-4.
- .
- ^ ISSN 2297-8739.
- ISSN 0149-6395.
- ISBN 978-3-319-48765-6.
- ISBN 978-3-030-58069-8.
- ISBN 978-0-07-136076-0. Retrieved 2011-03-18.
- ISBN 978-0-8031-3497-3. Retrieved 2011-03-18.
- ^ ISBN 978-0-08-037941-8.
- ^ a b "Zirconia". AZoM.com. 2008. Archived from the original on 2009-01-26. Retrieved 2008-03-17.
- .
- doi:10.1086/145937.
- .
- ISBN 978-1-4471-4194-5.
- ISSN 1098-0121.
- ^ doi:10.14529/chem230102.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ISBN 978-0273742753.
- ^ MSDS sheet for Duratec 400, DuBois Chemicals, Inc.
- ISSN 0009-2347. Retrieved 2008-03-17.
- .
- .
- ^ ISBN 978-0-313-30123-0.
- ^ Hedrick, James B. (1998). "Zirconium". Metal Prices in the United States through 1998 (PDF). US Geological Survey. pp. 175–178. Retrieved 2008-02-26.
- ^ "Fine ceramics – zirconia". Kyocera Inc.
- doi:10.2113/0530277.
External links
- Chemistry in its element podcast (MP3) from the Royal Society of Chemistry's Chemistry World: Zirconium
- Zirconium at The Periodic Table of Videos(University of Nottingham)