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zirconium

 
Dictionary: zir·co·ni·um   (zûr-kō'nē-əm) pronunciation
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n. (Symbol Zr)
A lustrous, grayish-white, strong, ductile metallic element obtained primarily from zircon and used chiefly in ceramic and refractory compounds, as an alloying agent, and in nuclear reactors as a highly corrosion-resistant alloy. Atomic number 40; atomic weight 91.22; melting point 1,852°C; boiling point 4,377°C; specific gravity 6.56 (20°C); valence 2, 3, 4.


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How Products are Made: How is zirconium made?
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Background

Zirconium, symbol Zr on the Periodic Table, is a metal most often found in and extracted from the silicate mineral zirconium silicate and the oxide mineral baddeleyite. In its various compound forms, the grayish-white zirconium is the nineteenth most plentiful element in the earth's crust, where it is far more abundant than copper and lead. It belongs to the titanium family of metals, a group that also includes titanium and hafnium and that is favored in industry for its members' good electrical conductivity as well as their tendency to form metallic salts. Because it is stable in many electron configurations and physical states, zirconium can be made into many products. However, since the 1940s, its most significant applications have been in various structural components of nuclear reactors.

Zirconium was discovered by German chemist Martin Heinrich Klaproth, who first isolated an oxide of the mineral zircon in 1789. The first metallic powder was produced in 1824 by a Swedish Chemist, Jons J. Berzelius. The forms of the metal that could be isolated during the nineteenth century, however, were impure and thus very brittle. The earliest method of purifying useable quantities of the metal was developed in 1925 by Dutch chemists Anton E. van Arkel and J. H. de Boer, who invented a thermal iodide process by which they thermally decomposed zirconium tetraiodide. The drawback with van Arkel and de Boer's method was its cost, but twenty years later William Justin Kroll of Luxembourg invented a cheaper process, using magnesium to break down zirconium tetrachloride. Relatively inexpensive, this process produced zirconium in quantities large and pure enough for industrial use.

Since Kroll's breakthrough, zirconium has become an important element in several industries: steel, iron, and nuclear power. It is used in the steel industry to remove nitrogen and sulfur from iron, thereby enhancing the metallurgical quality of the steel. When added to iron to create an alloy, zirconium improves iron's machinability, toughness, and ductility. Other common industrial applications of zirconium include the manufacture of photoflash bulbs and surgical equipment, and the tanning of leather.

Despite its ability to be used for many different industrial applications, most of the zirconium produced today is used in water-cooled nuclear reactors. Zirconium has strong corrosion-resistance properties as well as the ability to confine fission fragments and neutrons so that thermal or slow neutrons are not absorbed and wasted, thus improving the efficiency of the nuclear reactor. In fact, about 90 percent of the zirconium produced in 1989 was used in nuclear reactors, either in fuel containers or nuclear product casings.

Raw Materials

Of the two mineral forms in which zirconium occurs, zircon is by far the more important source. Found mainly in igneous rock, zircon also appears in the gravel and sand produced as igneous rock erodes. In this form, it is often mixed with silica, ilmenite, and rutile. The vast majority of the zircon used in industry today originates in these sand and gravel deposits, from which the purest zircon is extracted and refined to be used as zirconium metals. Less pure deposits are used in the form of stabilized zirconia for refractories and ceramic products. The world's largest zircon mines are in Australia, South Africa, and the United States, but rich beds also exist in Brazil, China, India, Russia, Italy, Norway, Thailand, Madagascar, and Canada. Like zircon, baddeleyite is extracted from sand and gravel deposits. Unlike zircon, commercially viable baddeleyite deposits contain relatively high concentrations of zirconium oxide, and baddeleyite can thus be used without refining. The mineral is, however, much more scarce than zircon, with significant amounts occurring only in Brazil and Florida.

Extraction and Refining

Extracting zircon

  • The sand and gravel that contain zircon mixed with silicate, ilmenite, and rutile are typically collected from coastal waters by a floating dredge, a large steam shovel fitted on a floating barge. After the shovel has scooped up the gravel and sand, they are purified by means of spiral concentrators, which separate on the basis of density. The ilmenite and rutile are then removed by magnetic and electrostatic separators. The purest concentrates of zircon are shipped to end-product manufacturers to be used in metal production, while less pure concentrations are used for refractories.

Refining zircon

  • End-product manufacturers of zircon further refine the nearly pure zircon into zirconium by using a reducing agent (usually chlorine) to purify the metal and then sintering (heating) it until it becomes sufficiently ductile—workable—for industrial use. For small-scale laboratory use, zirconium metal may be produced by means of a chemical reaction in which chloride is used to reduce the zircon.
  • The less-pure zircon is made into zirconia, an oxide of zirconium, by fusing the zircon with coke, iron borings, and lime until the silica is reduced to silicon that alloys with the iron. The zirconia is then stabilized by heating it to about 3,095 degrees Fahrenheit (1,700 degrees Celsius), with additions of lime and magnesia totalling about five percent.

Refining baddeleyite

  • As mentioned above, baddeleyite contains relatively high, pure concentrations of zirconium oxide that can be used without filtering or cleansing. The only refining process used on baddeleyite involves grinding the gravel or sand to a powder and sizing the powder with different sized sieves. All zirconium oxide that comes from baddeleyite is used for refractories and, increasingly, advanced ceramics.

Quality Control

The quality control methods implemented in the production of zirconium metal are typical Statistical Process Control (SPC) methods used in most metal production. These involve tracking and controlling specific variables determined by the end product requirements. Stringent government quality control is applied to all zirconium metal produced for nuclear applications. These controls assure that the zirconium produced for use in a nuclear plant has been processed correctly and also allow for accountability: processing is tracked so that it can be traced back to each individual step and location.

Quality control methods for zirconium used in refractory applications also focus on SPC. However, in the refractory industries, it is also necessary to ascertain the beach (and even what part of the beach) from which the zirconium mineral was extracted. Manufacturers need to know exactly where the zirconium came from because each source contains slightly different trace elements, and different trace elements can affect the end product.

Byproducts/Waste

Silicate, ilmenite, and rutile—all byproducts of the zircon refining process—are typically dumped back in the water at the extraction site. These elements compose typical beach sand and are in no way detrimental to the environment. Magnesium chloride, the only other notable byproduct of zirconium manufacturing, results from the reduction of the zircon with chlorine in the refining process and is typically sold to magnesium refineries. No byproducts or waste result from baddeleyite refining.

The Future

Many believe that the future of zirconium lies in its use as an advanced ceramic. Advanced ceramics—also called "fine," "new," "high-tech," or "high-performance" ceramics—are generally used as components in processing equipment, devices, or machines because they can perform many functions better than competing metals or polymers. Zirconium is fairly hard, doesn't conduct heat well, and is relatively inert (i.e., it doesn't react readily with other elements), all excellent qualities for advanced ceramics. Zirconium oxide, manufactured as a ceramic, can be used to make crucibles for melting metals, gas turbines, liners for jet and rocket motor tubes, resistance furnaces, ultra-high frequency furnaces, and refractories such as the facing of a high-temperature furnace wall.

Where To Learn More

Books

Heuer, A. H., ed. Science and Technology of Zirconia. American Ceramic Society, 1981.

Specifications for Zirconium and Zirconium Alloy Welding Electrodes and Rods. American Welding Society, 1990.

Zirconium and Hafnium. Gordon Press Publishers, 1993.

Periodicals

Burke, Marshall A. "Ceramics Enter the Foundry," Design News. June 16,1986, p. 56.

"Fuel Cell's Future Gets a Boost," Design News. August 18, 1986, p. 38.

"Zirconium," Machine Design. April 14, 1988, pp. 234-35.

"Zirconium Holds Down Costs of Making Zirconium," Metal Progress. November, 1983, pp. 11-12.

"Adding Strength to Glassy Ceramics," Science News. September 13, 1986, p. 170.

[Article by: Alicia Haley and; Blaine Danley]


Sci-Tech Encyclopedia: Zirconium
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A chemical element, Zr, atomic number 40, atomic weight 91.22. Its naturally occurring isotopes are 90, 91, 92, 94, and 96. Zirconium is one of the more abundant elements, and is widely distributed in the Earth's crust. Being very reactive chemically, it is found only in the combined state. Under most conditions, it bonds with oxygen in preference to any other element, and it occurs in the Earth's crust only as the oxide, ZrO2, baddeleyite, or as part of a complex of oxides as in zircon, elpidite, and eudialyte. Zircon is commercially the most important ore. Zirconium and hafnium are practically indistinguishable in chemical properties, and occur only together. See also Hafnium; Periodic table; Zircon.

Most of the zirconium used has been as compounds for the ceramic industry: refractories, glazes, enamels, foundry mold and core washes, abrasive grits, and components of electrical ceramics, The incorporation of zirconium oxide in glass significantly increases its resistance to alkali. The use of zirconium metal is almost entirely for cladding uranium fuel elements for nuclear power plants. Another significant use has been in photo flashbulbs.

Zirconium is a lustrous, silvery metal, with a density of 6.5 g/cm3 (3.8 oz/in.3) at 20°C (68°F). It melts at about 1850°C (3362°F). Estimates of the boiling point from appropriate data have commonly been of the order of 3600°C (6500°F), but observations suggest about 8600°C (15,500°F). The free energies of formation of its compounds indicate that zirconium should react with any nonmetal, other than the inert gases, at ordinary temperatures. In practice, the metal is found to be nonreactive near room temperature because of an invisible, impervious oxide film on its surface. The film renders the metal passive, and it remains bright and shiny in ordinary air indefinitely. At elevated temperatures it is very reactive to the non-metallic elements and many of the metallic elements, forming either solid solutions or compounds.

Zirconium generally has normal covalency of 4, and commonly exhibits coordinate covalencies of 5, 6, 7, and 8. Zirconium is at oxidation number 4 in nearly all of its compounds, Halides in which its oxidation numbers are 3 and 2 have been prepared. While zirconium is often part of cationic or anionic complexes, there is no definite evidence for a monatomic zirconium ion in any of its compounds.

Most handling and testing of zirconium compounds have indicated no toxicity. There has generally been no ill consequence of contact of zirconium compounds with the unabraded skin. However, some individuals appear to have allergic sensitivity to zirconium compounds, characteristically manifested by appearance of nonmalignant granulomas. Inhalation of sprays containing some zirconium compounds and of metallic zirconium dusts have had inflammatory effects.

Dental Dictionary: zirconium
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n
Zr

A metallic element with an atomic number of 40 and an atomic weight of 91.22. It is widely distributed in nature, although no concentrations are found in any one place.

Britannica Concise Encyclopedia: zirconium
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Metallic chemical element, one of the transition elements, chemical symbol Zr, atomic number 40. The metal is hard and brittle when impure, soft and ductile when highly purified. It is relatively abundant, occurring as zircon (also marketed as a natural gemstone) and baddeleyite. Highly transparent to neutrons, zirconium became important in the 1940s in nuclear energy applications such as fuel cladding. Other uses are in alloys, fireworks, and flashbulbs and as a scavenger for oxygen and other gases. Its compounds, in most of which it has valence 4, are important industrial materials. Zirconia (the oxide) is used in piezoelectric crystals (see piezoelectricity), high-frequency induction coils, coloured glazes and glasses, and heat-resistant fibres; zirconium carbonate is employed in preparations to treat the rash of poison ivy.

For more information on zirconium, visit Britannica.com.

 
Columbia Encyclopedia: zirconium
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zirconium (zərkō'nēəm), metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.22; m.p. about 1,852°C; b.p. 4,377°C; sp. gr. 6.5 at 20°C; valence +2, +3, or +4.

Zirconium is a very strong, malleable, ductile, lustrous silver-gray metal. At ordinary temperatures it has a hexagonal close-packed crystalline structure. Its chemical and physical properties are similar to those of titanium, the element above it in Group 4 of the periodic table. Zirconium is extremely resistant to heat and corrosion. It forms a number of compounds, among them zirconate (ZrO3−2) and zirconyl (ZrO+2) salts.

The most important compound is the oxide zirconia (ZrO2), used extensively as a refractory material in furnaces and crucibles, in ceramic glazes, and, formerly, in gas mantles. It occurs in nature as the silicate (ZrSiO4) and is used as a gemstone; it may be clear or colored, and is usually called zircon or hyacinth. Zirconium compounds also have minor uses as catalysts, in the dye, textile, plastics, and paint industries, and in pharmaceuticals such as poison ivy lotions.

The metal also has many other uses, among them in photographic flashbulbs and surgical instruments, in the removal of residual gases from electronic vacuum tubes, and as a hardening agent in alloys, especially steel. A major use of the metal is in nuclear reactors. It is employed in tubes for cladding uranium oxide fuel. It is well suited for this purpose because it is corrosion resistant and does not readily absorb thermal neutrons. It is specially purified to remove hafnium, which absorbs neutrons much more readily. It is usually alloyed with other metals to make it more corrosion resistant for these uses.

Zirconium is a fairly abundant element and is widely distributed in minerals, but it is never found uncombined in nature. It always occurs with hafnium, which has almost identical chemical properties. The chief ore is zircon (the silicate); baddeleyite (the oxide) also has some importance. Zircon is recovered (along with monazite, ilmenite, and rutile) from certain beach sands in New South Wales, Australia, and near Jacksonville, Fla. The metal is produced by the Kroll process. The zircon is treated with carbon in an electric furnace to form a cyanonitride, which is in turn treated with chlorine gas to form the volatile tetrachloride. The tetrachloride is carefully purified by sublimation in an inert atmosphere and is then chemically reduced to metal sponge by reaction with molten magnesium. The spongy metal is cleaned and further processed into ingots.

Special care is taken to exclude hydrogen, nitrogen, and oxygen, which make the metal brittle. If the metal is too brittle to be worked, it can be further purified by the Van Arkel-de Boer process, in which the crude metal is reacted with iodine to form volatile iodides that are thermally decomposed on a hot wire, resulting in pure crystalline zirconium. The commercial metal usually contains between 1% and 3% hafnium; for nuclear reactor use the hafnium is usually removed by solvent extraction from the tetrachloride. Zirconium was discovered as the oxide zirconia in the mineral zircon by M. H. Klaproth in 1789 and was first isolated in impure form by J. J. Berzelius in 1824.

Veterinary Dictionary: zirconium
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A chemical element, atomic number 40, atomic weight 91.22, symbol Zr.

  • z. chlorhydrate — an astringent.
Wikipedia: Zirconium
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yttrium ← zirconium → niobium
Ti
↑
Zr
↓
Hf
Appearance
silvery white
General properties
Name, symbol, number zirconium, Zr, 40
Element category transition metal
Group, period, block 4, 5, d
Standard atomic weight 91.224 g·mol−1
Electron configuration [Kr] 4d2 5s2
Electrons per shell 2, 8, 18, 10, 2 (Image)
Physical properties
Phase solid
Density (near r.t.) 6.52 g·cm−3
Liquid density at m.p. 5.8 g·cm−3
Melting point 2128 K, 1855 °C, 3371 °F
Boiling point 4682 K, 4409 °C, 7968 °F
Heat of fusion 14 kJ·mol−1
Heat of vaporization 573 kJ·mol−1
Specific heat capacity (25 °C) 25.36 J·mol−1·K−1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 2639 2891 3197 3575 4053 4678
Atomic properties
Oxidation states 4, 3, 2, 1,[1]
(amphoteric oxide)
Electronegativity 1.33 (Pauling scale)
Ionization energies 1st: 640.1 kJ·mol−1
2nd: 1270 kJ·mol−1
3rd: 2218 kJ·mol−1
Atomic radius 160 pm
Covalent radius 175±7 pm
Miscellanea
Crystal structure hexagonal close-packed
Magnetic ordering paramagnetic[2]
Electrical resistivity (20 °C) 421 nΩ·m
Thermal conductivity (300 K) 22.6 W·m−1·K−1
Thermal expansion (25 °C) 5.7 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3800 m/s
Young's modulus 88 GPa
Shear modulus 33 GPa
Bulk modulus 91.1 GPa
Poisson ratio 0.34
Mohs hardness 5.0
Vickers hardness 903 MPa
Brinell hardness 650 MPa
CAS registry number 7440-67-7
Most stable isotopes
Main article: Isotopes of zirconium
iso NA half-life DM DE (MeV) DP
88Zr syn 83.4 d ε - 88Y
γ 0.392D -
89Zr syn 78.4 h ε - 89Y
β+ 0.902 89Y
γ 0.909D -
90Zr 51.45% 90Zr is stable with 50 neutrons
91Zr 11.22% 91Zr is stable with 51 neutrons
92Zr 17.15% 92Zr is stable with 52 neutrons
93Zr trace 1.53×106 y β− 0.060 93Nb
94Zr 17.38% 1.1×1017 y β−β− - 94Mo
96Zr 2.8% 2.0×1019 y[3] β−β− 3.348 96Mo
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Zirconium (pronounced /zərˈkoʊniəm/ zər-KOH-nee-əm) is a chemical element with the symbol Zr and atomic number 40. It is a lustrous, gray-white, strong transition metal that resembles titanium. Zirconium is used as an alloying agent due to its high resistance to corrosion. It is never found as a native metal; it is obtained mainly from the mineral zircon, which can be purified by chlorine. Zirconium was first isolated in an impure form in 1824 by Jöns Jakob Berzelius.

Zirconium has no known biological role. Zirconium forms both inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. There are five naturally-occurring isotopes, three of which are stable. Short-term exposure to zirconium powder causes minor irritation, and inhalation of zirconium compounds can cause skin and lung granulomas.

Contents

Characteristics

Zirconium is a lustrous, grayish-white, soft, ductile, and malleable metal which is solid at room temperature, though it becomes hard and brittle at lower purities.[4][5] In powder form, zirconium is highly flammable, but the solid form is far less prone to igniting. Zirconium is highly resistant to corrosion by alkalis, acids, salt water, and other agents.[6] However, it will dissolve in hydrochloric and sulfuric acid, especially when fluorine is present.[7] Alloys with zinc become magnetic below 35 K.[6]

The melting point of zirconium is at 1855°C, and the boiling point is at 4409°C.[6] Zirconium has an electronegativity of 1.33 on the Pauling scale. Of the elements within d-block, zirconium has the fourth lowest electronegativity after yttrium, lutetium, and hafnium.[8]

Applications

Because of zirconium's excellent resistance to corrosion, it is often used as an alloying agent in materials that are exposed to corrosive agents, such as surgical appliances, explosive primers, vacuum tube getters and filaments. Zirconium dioxide (ZrO2) is used in laboratory crucibles, metallurgical furnaces, and as a refractory material.[6] Zircon (ZrSiO4) is cut into gemstones for use in jewelry. Zirconium carbonate (3ZrO2·CO2·H2O) was used in lotions to treat poison ivy, but this was discontinued as it caused bad skin reactions in some cases.[4] 90% of all zirconium produced is used in nuclear reactors because of its low neutron-capture cross-section and resistance to corrosion.[5][6] Zirconium alloys are used in space vehicle parts for their resistance to heat, an important quality given the extreme heat associated with atmospheric reentry.[9] Zirconium is also a component in some abrasives, such as grinding wheels and sandpaper.[10] Zirconium is used in weapons such as the BLU-97/B Combined Effects Bomb for incendiary effect. Zirconium in the oxidized form is also used in dentistry for crowning of the teeth because of its biocompatibility, strength and appearance. High temperature parts such as combustors, blades and vanes in modern jet engines and stationary gas turbines are to an ever increasing extent being protected by thin ceramic layers which reduce the metal temperatures below and keep them from undergoing (too) extensive deformation which could possibly result in early failure. They are absolutely necessary for the most modern gas turbines which are driven to ever higher firing temperatures to produce more electricity at less CO2. These ceramic layers are usually composed by a mixture of zirconium and yttrium oxide.[citation needed]

Refining

Upon being collected from coastal waters, the solid mineral zircon is purified by spiral concentrators to remove excess sand and gravel and by magnetic separators to remove ilmenite and rutile. The byproducts can then be dumped back into the water safely, as they are all natural components of beach sand. The refined zircon is then purified into pure zirconium by chlorine or other agents, then sintered until sufficiently ductile for metalworking.[5] Zirconium and hafnium are both contained in zircon and they are quite difficult to separate due to their similar chemical properties.[9]

History

Zirconium crystal bar, 99,97%, made by the crystal bar process

The zirconium-containing mineral zircon, or its variations (jargoon, hyacinth, jacinth, ligure), were mentioned in biblical writings.[6][9] The mineral was not known to contain a new element until 1789,[10] when Klaproth analyzed a jargoon from the island of Sri Lanka in the Indian Ocean. He named the new element Zirkonerde (zirconia).[6] Humphry Davy attempted to isolate this new element in 1808 through electrolysis, but failed.[4] Zirconium (from Syriac zargono,[11] Arabic zarkûn from Persian zargûn زرگون meaning "gold like")[9] was first isolated in an impure form in 1824 by Berzelius by heating a mixture of potassium and potassium-zirconium fluoride in a small decomposition process conducted in an iron tube.[6]

The crystal bar process (or 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 pure metallic zirconium. The process involved thermally decomposing zirconium tetraiodide. It was superseded in 1945 by the much cheaper Kroll process developed by William Justin Kroll, in which zirconium tetrachloride is broken down by magnesium.[5][12]

Occurrence

Geological

Zirconium output in 2005
World production trend of zirconium mineral concentrates

Zirconium has a concentration of about 130 mg/kg within the earth's crust and about .026 μg/L in sea water,[13] though it is never found in nature as a native metal. The principal commercial source of zirconium is the zirconium silicate mineral, zircon (ZrSiO4),[4] which is found primarily in Australia, Brazil, India, Russia, South Africa, and the United States, as well as in smaller deposits around the world.[5] 80% of zircon mining occurs in Australia and South Africa.[4] Zircon resources exceed 60 million metric tons worldwide[14] and annual worldwide zirconium production is approximately 900,000 metric tons.[13]

Zircon is a by-product of the mining and processing of the titanium minerals ilmenite and rutile, as well as tin mining.[15] From 2003 to 2007, zircon prices have steadily increased from $360 to $840 per metric ton.[14] Zirconium also occurs in more than 140 other recognized mineral species including baddeleyite and kosnarite.[16] This metal is commercially produced mostly by the reduction of the zirconium(IV) chloride with magnesium metal in the Kroll process.[6] Commercial-quality zirconium for most uses still has a content of 1% to 3% hafnium.[4]

This element is relatively-abundant in S-type stars, and it has been detected in the sun and in meteorites. Lunar rock samples brought back from several Apollo program missions to the moon have a quite high zirconium oxide content relative to terrestrial rocks.[6]

See also zirconium minerals.

Biological

Zirconium has no known biological role, though zirconium salts are of low toxicity. The human body contains, on average, only 1 milligram of zirconium, and daily intake is approximately 50 μg per day. Zirconium content in human blood is as low as 10 parts per billion. Aquatic plants readily take up soluble zirconium, but it is rare in land plants. 70% of plants have no zirconium content at all, and those that do have as little as 5 parts per billion.[4]

Compounds

See also: Category:Zirconium compounds

As a transition metal, zirconium forms various inorganic compounds, such as zirconium dioxide (ZrO2). This compound, also referred to as zirconia, has exceptional fracture toughness and chemical resistance, especially in its cubic form.[17] These properties make zirconia useful as a thermal barrier coating,[18] though it is also a common diamond substitute.[17] Zirconium tungstate is an unusual substance in that it shrinks in all directions when heated, whereas other elements expand when heated.[6] ZrZn2 is one of only two substances to exhibit superconductivity and ferromagnetism simultaneously, with the other being UGe2.[19] Other inorganic zirconium compounds include zirconium(II) hydride, zirconium nitride, and zirconium tetrachloride (ZrCl4), which is used in the Friedel-Crafts reaction.[20]

Organozirconium chemistry is the study of compounds containing a carbon-zirconium bond. These organozirconium compounds are often employed as polymerization catalysts. The first such compound was zirconocene dibromide, prepared in 1952 by John M. Birmingham at Harvard University.[21] Schwartz's reagent, prepared in 1970 by P. C. Wailes and H. Weigold,[22] is a metallocene used in organic synthesis for transformations of alkenes and alkynes.[23]

Isotopes

A zirconium rod
Main article: Isotopes of zirconium

Naturally-occurring zirconium is composed of five isotopes. 90Zr, 91Zr, and 92Zr are stable. 94Zr has a half-life of 1.10×1017 years. 96Zr has a half-life of 2.4×1019 years, making it 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.[24]

28 artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 78 to 110. 93Zr is the longest-lived artificial isotope, with a half-life of 1.53×106 years. 110Zr, the heaviest isotope of zirconium, is also the shortest-lived, with an estimated half-life of only 30 milliseconds. Radioactive isotopes at or above mass number 93 decay by β−, whereas those at or below 89 decay by β+. The only exception is 88Zr, which decays by ε.[24]

Zirconium also has six metastable isomers: 83mZr, 85mZr, 89mZr, 90m1Zr, 90m2Zr, and 91mZr. Of these, 90m2Zr has the shortest half-life at 131 nanoseconds. 89mZr is the longest lived with a half-life of 4.161 minutes.[24]

Toxicity

Short-term exposure to zirconium powder can cause irritation, but only contact with the eyes requires medical attention.[25] Inhalation of zirconium compounds can cause skin and lung granulomas. Zirconium aerosols can cause pulmonary granulomas. Persistent exposure to zirconium tetrachloride resulted in increased mortality in rats and guinea pigs and a decrease of blood hemoglobin and red blood cells in dogs. OSHA recommends a 5 mg/m3 time weighted average limit and a 10 mg/m3 short-term exposure limit.[26]

See also

Notes

  1. ^ "Zirconium: zirconium(I) fluoride compound data". OpenMOPAC.net. http://openmopac.net/data_normal/zirconium(i)%20fluoride_jmol.html. Retrieved 2007-12-10. 
  2. ^ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81th edition, CRC press.
  3. ^ Pritychenko, Boris; V. Tretyak. "Adopted Double Beta Decay Data". National Nuclear Data Center. http://www.nndc.bnl.gov/bbdecay/list.html. Retrieved 2008-02-11. 
  4. ^ a b c d e f g Emsley, John (2001). Nature's Building Blocks. Oxford: Oxford University Press. pp. 506–510. ISBN 0-19-850341-5. 
  5. ^ a b c d e "Zirconium". How Products Are Made. Advameg Inc.. 2007. http://www.madehow.com/Volume-1/Zirconium.html. Retrieved 2008-03-26. 
  6. ^ a b c d e f g h i j k Lide, David R., ed. (2007–2008), "Zirconium", CRC Handbook of Chemistry and Physics, 4, New York: CRC Press, pp. 42, 978-0-8493-0488-0 
  7. ^ Considine, Glenn D., ed. (2005), "Zirconium", Van Nostrand's Encyclopedia of Chemistry, New York: Wylie-Interscience, pp. 1778–1779, ISBN 0-471-61525-0 
  8. ^ Winter, Mark (2007). "Electronegativity (Pauling)". University of Sheffield. http://www.webelements.com/webelements/properties/text/image-flash/electroneg-pauling.html. Retrieved 2008-03-05. 
  9. ^ a b c d Stwertka, Albert (1996). A Guide to the Elements. Oxford University Press. pp. 117–119. ISBN 0-19-508083-1. 
  10. ^ a b Krebs, Robert E. (1998). The History and Use of our Earth's Chemical Elements. Westport, Connecticut: Greenwood Press. pp. 98–100. ISBN 0-313-30123-9. 
  11. ^ Pearse, Roger (2002-09-16). "Syriac Literature". http://www.tertullian.org/rpearse/oriental/syriac.htm. Retrieved 2008-02-11. 
  12. ^ Hedrick, James B. (1998), "Zirconium" (PDF), Metal Prices in the United States through 1998, US Geological Survey, pp. 175–178, http://minerals.usgs.gov/minerals/pubs/metal_prices/metal_prices1998.pdf, retrieved 2008-02-26 
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Translations: Zirconium
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Dansk (Danish)
n. - zirkonium, zirconium

Nederlands (Dutch)
zirkoon (element 40)

Français (French)
n. - zirconium

Deutsch (German)
n. - (chem.) Zirkonium

Ελληνική (Greek)
n. - ζιρκόνιο

Italiano (Italian)
zirconio

Português (Portuguese)
n. - zircônio (m) (Quím.)

Русский (Russian)
цирконий

Español (Spanish)
n. - circonio, zirconio

Svenska (Swedish)
n. - zirkonium (kem.)

中文（简体）(Chinese (Simplified))
锆

中文（繁體）(Chinese (Traditional))
n. - 鋯

한국어 (Korean)
n. - 지르코늄(금속원소;기호Zr,번호 40)

日本語 (Japanese)
n. - ジルコニウム

العربيه (Arabic)
‏(الاسم) زركونيوم ( عنصر فلزي رمزه الكيماوي " كن)"‏

עברית (Hebrew)
n. - ‮זירקון (יסוד, RZ, מס' אטומי 04)‬

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zircaloy
beryllide (inorganic chemistry)

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