Zirconium
Template:Elementbox header Template:Elementbox series Template:Elementbox groupperiodblock Template:Elementbox appearance img Template:Elementbox atomicmass gpm Template:Elementbox econfig Template:Elementbox epershell Template:Elementbox section physicalprop Template:Elementbox phase Template:Elementbox density gpcm3nrt Template:Elementbox densityliq gpcm3mp Template:Elementbox meltingpoint Template:Elementbox boilingpoint Template:Elementbox heatfusion kjpmol Template:Elementbox heatvaporiz kjpmol Template:Elementbox heatcapacity jpmolkat25 Template:Elementbox vaporpressure katpa Template:Elementbox section atomicprop Template:Elementbox crystalstruct Template:Elementbox oxistates Template:Elementbox electroneg pauling Template:Elementbox ionizationenergies4 Template:Elementbox atomicradius pm Template:Elementbox atomicradiuscalc pm Template:Elementbox covalentradius pm Template:Elementbox section miscellaneous Template:Elementbox magnetic Template:Elementbox eresist ohmmat20 Template:Elementbox thermalcond wpmkat300k Template:Elementbox thermalexpansion umpmkat25 Template:Elementbox speedofsound rodmpsat20 Template:Elementbox youngsmodulus gpa Template:Elementbox shearmodulus gpa Template:Elementbox poissonratio Template:Elementbox mohshardness Template:Elementbox vickershardness mpa Template:Elementbox brinellhardness mpa Template:Elementbox cas number Template:Elementbox isotopes begin |- ! rowspan="2" style="text-align:right; vertical-align:middle;" | 88Zr | rowspan="2" style="text-align:center; vertical-align:middle;" | syn | rowspan="2" style="text-align:right; vertical-align:middle;" | 83.4 d | ε | style="text-align:right;" | 88Y |- | γ | style="text-align:right;" | - |- ! rowspan="3" style="text-align:right; vertical-align:middle;" | 89Zr | rowspan="3" style="vertical-align:middle; text-align:center" | syn | rowspan="3" style="vertical-align:middle; text-align:right;" | 78.4 h | ε | style="text-align:right;" | 89Y |- | β+ | style="text-align:right;" | 89Y |- | γ | style="text-align:right;" | - Template:Elementbox isotopes stable Template:Elementbox isotopes stable Template:Elementbox isotopes stable |- ! style="text-align:right;" | 93Zr | style="text-align:center;" | syn | style="text-align:right;" | 1.53×106y | β− | style="text-align:right;" | 93Nb |- ! style="text-align:right;" | 94Zr | style="text-align:right;" | 17.38% | style="text-align:right;" | 1.1 × 1017 y | β−β− | style="text-align:right;" | 94Mo |- ! style="text-align:right;" | 96Zr | style="text-align:right;" | 2.8% | style="text-align:right;" | 2.0×1019y [1] | β−β− | style="text-align:right;" | 96Mo Template:Elementbox isotopes end Template:Elementbox footer
Zirconium (Template:PronEng, /ˌzɝˈkoʊniəm/) 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 never found as a native metal, but is instead obtained mainly from the mineral zircon. Zirconium is used as an alloying agent due to its high resistance to corrosion.
Characteristics
Zirconium is a lustrous, grayish-white metal which is solid at room temperature. In powder form, zirconium is highly flammable, but the solid form is far less prone to igniting.[2] Zirconium is highly resistant to corrosion by alkalis, acids, salt water, and other agents.[3] Alloys with zinc become magnetic below 35 K.[4]
The melting point of zirconium is at 1852°C, and the boiling point is at 4377°C.[5] 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.[6]
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.[4] Zircon (ZrSiO4) is cut into gemstones for use in jewelry. Zirconium carbonate (3ZrO2·CO2·H2O) is used in lotions to treat poison ivy. Zirconium is also used in nuclear reactors because of its low neutron-capture cross-section and resistance to corrosion.[7]
History
Zirconium (from Syriac zargono,[8] Arabic zarkûn from Persian zargûn زرگون meaning "gold like") was discovered in 1789 by Martin Heinrich Klaproth, isolated in 1824 by Jöns Jakob Berzelius, and finally put in a pure form in 1914.[7]
The zirconium-containing mineral zircon, or its variations (jargoon, hyacinth, jacinth, ligure), were mentioned in biblical writings. The mineral was not known to contain a new element until Klaproth analyzed a jargoon from the island of Ceylon in the Indian Ocean. He named the new element Zirkonertz (zirconia). The impure metal was isolated first by Berzelius by heating a mixture of potassium and potassium-zirconium fluoride in a small decomposition process conducted in an iron tube.[3]
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. It was superseded by the Kroll process, developed in the 1940s.[9]
Occurrence
Zirconium has a concentration of about 130 mg/kg within the earth's crust and about .026 μg/L in sea water,[10] though it is never found in nature as a native metal. The principal commercial source of zirconium is the zirconium silicate mineral, zircon (ZrSiO4), which is found in deposits located in Australia, Brazil, India, Russia, and the United States. Zirconium and hafnium are both contained in zircon and they are quite difficult to separate chemically.[11] Zircon resources exceed 60 million metric tons worldwide[12] and annual worldwide zirconium production is approximately 900,000 metric tons.[10]
Zircon is a by-product of the mining and processing of the titanium minerals ilmenite and rutile, as well as tin mining.[13] From 2003 to 2007, zircon prices have steadily increased from $360 to $840 per metric ton.[12] Zirconium also occurs in more than 140 other recognized mineral species including baddeleyite and kosnarite.[14] This metal is commercially produced mostly by the reduction of the zirconium(IV) chloride with magnesium metal in the Kroll process. Commercial-quality zirconium for most uses still has a content of 1% to 3% hafnium.[5]
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.[3][11]
See also zirconium minerals.
Isotopes
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 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.[15]
28 artificial isotopes of zirconium have been synthesized, ranging in atomic mass from 78 to 110. 93Zr is 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.[15]
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.[15]
Toxicity
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.[16] Ingestion or inhalation of 93Zr, a radioactive isotope, causes a slight increase in the likelihood of developing cancer.[10]
References
- ^ Pritychenko, Boris. "Adopted Double Beta Decay Data". National Nuclear Data Center. Retrieved 2008-02-11.
{{cite web}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Winter, Mark (2007). "Key Information". Zirconium. University of Sheffield. Retrieved 2008-02-12.
- ^ a b c "Zirconium". Los Alamos Chemistry Division. 2003-12-15. Retrieved 2008-02-12.
- ^ a b Winter, Mark (2007). "Uses". Zirconium. University of Sheffield. Retrieved 2008-02-12.
- ^ a b "Zirconium". Infoplease. Pearson Education. 2007. Retrieved 2008-02-24.
- ^ Winter, Mark (2007). "Electronegativity (Pauling)". University of Sheffield. Retrieved 2008-03-05.
- ^ a b Gagnon, Steve. "Zirconium". It's Elemental. Jefferson Lab. Retrieved 2008-02-12.
- ^ Pearse, Roger (2002-09-16). "Syriac Literature". Retrieved 2008-02-11.
- ^ Hedrick, James B. (1998), "Zirconium", Metal Prices in the United States through 1998 (PDF), US Geological Survey, pp. 175–178, retrieved 2008-02-26
- ^ a b c 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, retrieved 2008-02-26
- ^ a b Winter, Mark (2007). "Geological Information". Zirconium. University of Sheffield. Retrieved 2008-02-19.
- ^ a b "Zirconium and Hafnium" (PDF). Mineral Commodity Summaries. US Geological Survey: 192–193. January 2008. Retrieved 2008-02-24.
- ^ Callaghan, R. (2008-02-21). "Zirconium and Hafnium Statistics and Information". US Geological Survey. Retrieved 2008-02-24.
- ^ Ralph, Jolyon (2008). "Minerals that include Zr". Mindat.org. Retrieved 2008-02-23.
{{cite web}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ a b c "Nubase2003 Evaluation of Nuclear and Decay Properties" (PDF). Nuclear Physics A. 729. Atomic Mass Data Center: 3–128. 2003. Retrieved 2008-03-04.
{{cite journal}}: Unknown parameter|formate=ignored (help) - ^ "Zirconium Compounds". National Institute for Occupational Health and Safety. 2007-12-17. Retrieved 2008-02-17.
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