View source for Zirconium

{{Elementbox_header | number=40 | symbol=Zr | name=zirconium | left=[[yttrium]] | right=[[niobium]] | above=[[titanium|Ti]] | below=[[hafnium|Hf]] | color1=#ffc0c0 | color2=black }}
{{Elementbox_series | [[transition metal]]s }}
{{Elementbox_groupperiodblock | group=4 | period=5 | block=d }}
{{Elementbox_appearance_img | Zr,40| silvery white }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|91.224]][[List of elements by atomic mass|(2)]] }}
{{Elementbox_econfig | &#91;[[krypton|Kr]]&#93; 4d<sup>2</sup> 5s<sup>2</sup> }}
{{Elementbox_epershell | 2, 8, 18, 10, 2 }}
{{Elementbox_section_physicalprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 6.52 }}
{{Elementbox_densityliq_gpcm3mp | 5.8 }}
{{Elementbox_meltingpoint | k=2128 | c=1855 | f=3371 }}
{{Elementbox_boilingpoint | k=4682 | c=4409 | f=7968 }}
{{Elementbox_heatfusion_kjpmol | 14 }}
{{Elementbox_heatvaporiz_kjpmol | 573 }}
{{Elementbox_heatcapacity_jpmolkat25 | 25.36 }}
{{Elementbox_vaporpressure_katpa | 2639 | 2891 | 3197 | 3575 | 4053 | 4678 | comment= }}
{{Elementbox_section_atomicprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_crystalstruct | [[Close-packing|hexagonal close-packed]] }}
{{Elementbox_oxistates | 4, 3,<ref>{{cite web|url=http://www.webelements.com/webelements/compounds/text/Zr/I3Zr1-13779878.html|title=Zirconium: zirconium(III) iodide compound data|accessdate=2007-12-10|publisher=WebElements.com}}</ref> 2, 1,<ref>{{cite web|url=http://openmopac.net/data_normal/zirconium(i)%20fluoride_jmol.html|title=Zirconium: zirconium(I) fluoride compound data|accessdate=2007-12-10|publisher=OpenMOPAC.net}}</ref><br />([[amphoteric]] oxide) }}
{{Elementbox_electroneg_pauling | 1.33 }}
{{Elementbox_ionizationenergies4 | 640.1 | 1270 | 2218 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|155]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|206]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|148]] }}
{{Elementbox_section_miscellaneous | color1=#ffc0c0 | color2=black }}
{{Elementbox_magnetic | no data }}
{{Elementbox_eresist_ohmmat20 | 421 n}}
{{Elementbox_thermalcond_wpmkat300k | 22.6 }}
{{Elementbox_thermalexpansion_umpmkat25 | 5.7 }}
{{Elementbox_speedofsound_rodmpsat20 | 3800 }}
{{Elementbox_youngsmodulus_gpa | 68 }}
{{Elementbox_shearmodulus_gpa | 33 }}
{{Elementbox_poissonratio | 0.34 }}
{{Elementbox_mohshardness | 5.0 }}
{{Elementbox_vickershardness_mpa | 903 }}
{{Elementbox_brinellhardness_mpa | 650 }}
{{Elementbox_cas_number | 7440-67-7 }}
{{Elementbox_isotopes_begin | color1=#ffc0c0 | color2=black }}
{{Elementbox_isotopes_decay2 | mn=88 | sym=Zr
 | na=[[synthetic radioisotope|syn]] | hl=[[1 E6 s|83.4 d]]
 | dm1=[[Electron capture|ε]] | de1=- | pn1=88 | ps1=[[yttrium|Y]]
 | dm2=[[gamma ray|γ]] | de2=0.392[[Delayed nuclear radiation|D]] | pn2= | ps2=- }}
{{Elementbox_isotopes_decay3 | mn=89 | sym=Zr
 | na=[[synthetic radioisotope|syn]] | hl=[[1 E5 s|78.4 h]]
 | dm1=[[Electron capture|ε]] | de1=- | pn1=89 | ps1=[[yttrium|Y]]
 | dm2=[[Positron emission|β<sup>+</sup>]] | de2=0.902 | pn2=89 | ps2=[[yttrium|Y]]
 | dm3=[[gamma ray|γ]] | de3=0.909[[Delayed nuclear radiation|D]] | pn3= | ps3=- }}
{{Elementbox_isotopes_stable | mn=90 | sym=Zr | na=51.45% | n=50 }}
{{Elementbox_isotopes_stable | mn=91 | sym=Zr | na=11.22% | n=51 }}
{{Elementbox_isotopes_stable | mn=92 | sym=Zr | na=17.15% | n=52 }}
{{Elementbox_isotopes_decay | mn=93 | sym=Zr
 | na=[[synthetic radioisotope|syn]] | hl=[[1 E13 s|1.53&times;10<sup>6</sup>y]]
 | dm=[[Beta emission|β<sup>−</sup>]] | de=0.060 | pn=93 | ps=[[niobium|Nb]] }}
{{Elementbox_isotopes_stable | mn=94 | sym=Zr | na=17.38% | n=54 }}
{{Elementbox_isotopes_decay | mn=96 | sym=Zr
 | na=2.8% | hl=[[1 E19 s|2.0&times;10<sup>19</sup>y]] <ref>[http://www.nndc.bnl.gov/bbdecay/index.jsp Double Beta Decay Transitions]</ref>
 | dm=[[double beta decay|β<sup>−</sup>β<sup>−</sup>]] | de=3.348 | pn=96 | ps=[[molybdenum|Mo]] }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffc0c0 | color2=black }}

'''Zirconium''' ({{pronEng|zɚˈkoʊniəm}}, {{IPA|/ˌzɝˈkoʊniəm/}}) is a [[chemical element]] that has the symbol '''Zr''' and has the [[atomic number]] 40. A lustrous, very corrosion resistant, gray-white, strong [[transition metal]] that resembles [[titanium]], zirconium is obtained mainly from the mineral [[zircon]]. Zirconium is primarily used in [[nuclear reactor]]s, especially in the cladding of the fuel rods, due to its low neutron-capture [[cross-section]] and its resistance to [[corrosion]].

== Characteristics ==
Zirconium is a grayish-white [[metal]], lustrous, and quite corrosion-resistant. Zirconium is lighter than [[steel]] and its hardness is similar to [[copper]]. When it is finely divided into a powder, zirconium can spontaneously ignite in air, especially at high temperatures. (It is much more difficult to ignite the solid metal.) The Zirconium-zinc [[alloy]] becomes [[magnetism|magnetic]] at temperatures below 35 [[Kelvin|K]]. The [[oxidation state]] of zirconium is usually +4, although +3 and +2 can also be obtained inside of chemical compounds.

==History==
Zirconium (from [[Syriac language|Syriac]] ''zargono'',<ref>http://www.tertullian.org/rpearse/oriental/syriac.htm</ref> [[Arabic language|Arabic]] ''zarkûn'' from [[Persian language|Persian]] ''zargûn'' ''زرگون'' meaning "gold like") was [[Discovery of the chemical elements|discovered]] in [[1789]] by [[Martin Heinrich Klaproth]], isolated in [[1824]] by [[Jöns Jakob Berzelius]], and finally put in a pure form in 1914.

The zirconium-containing [[mineral]] zircon, or its variations (jargon, hyacinth, jacinth, or ligure), were mentioned in biblical writings. The mineral was not known to contain a new element until Klaproth analyzed a jargon (what's a 'jargon' -- no answer in WK) 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. Pure zirconium wasn't prepared until 1914.

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 later superseded by the [[Kroll process]].

== Occurrence ==
[[Image:2005zirconium.PNG|thumb|left|Zirconium output in 2005]]
[[Image:Zirconium mineral concentrates - world production trend.svg|thumb|left|World production trend of zirconium mineral concentrates]]
Zirconium is never found in nature as a native metal. The principal economic source of zirconium is the zirconium [[silicate mineral]], [[zircon]] (ZrSiO<sub>4</sub>), which is found in deposits located in [[Australia]], [[South Africa]] and the [[United States]], as reported by the [[British Geological Survey]]. It is extracted either as a dark sooty powder, or as a gray metallic crystalline substance. Zirconium and [[hafnium]] are contained in zircon at a ratio of about 50 to 1, and they are quite difficult to separate chemically.  Zircon is a co-product or by-product of the mining and processing of heavy-mineral sands for the [[titanium]] minerals, [[ilmenite]] and [[rutile]], or from [[tin]] minerals. Zirconium also occurs in about 30 other recognized mineral species including [[baddeleyite]]. 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.

This element is relatively-abundant in [[Stellar classification#Class S|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.

''See also [[:category:Zirconium minerals|zirconium minerals]].''

== Isotopes ==
{{main|isotopes of zirconium}}
Naturally-occurring zirconium is composed of four stable isotopes, and one extremely long-lived [[radioisotope]] (<sup>96</sup>Zr). The second most stable radioisotope is [[Zr-93|<sup>93</sup>Zr]] which has a [[half-life]] of 1.53 million years.  Eighteen other radioisotopes have been observed. Most of these have half-lives that are less than a day except for <sup>95</sup>Zr (64.02 days), <sup>88</sup>Zr (63.4 days), and <sup>89</sup>Zr (78.41 hours). The primary decay mode is [[electron capture]] for isotopes lighter than <sup>92</sup>Zr, and the primary mode for heavier isotopes is [[beta decay]]. Other isotopes of zirconium include <sup>90</sup>Zr, <sup>91</sup>Zr, and <sup>94</sup>Zr

== Compounds ==
Some common zirconium compounds are: 
[[Zirconium carbide|ZrC]],
[[Zirconium dioxide|ZrO<sub>2</sub>]],
[[Zirconium nitride|ZrN]],
[[Zirconium tetrachloride|ZrCl<sub>4</sub>]],
[[Zirconium(IV) sulfide|ZrS<sub>2</sub>]],
[[Zirconium(IV) silicide|ZrSi<sub>2</sub>]],
[[Zirconium(IV) silicate|ZrSiO<sub>4</sub>]],
[[Zirconium(IV) fluoride|ZrF<sub>4</sub>]],
[[Zirconium(IV) bromide|ZrBr<sub>4</sub>]],
[[Zirconium(IV) iodide|ZrI<sub>4</sub>]],
[[Zirconium(IV) hydroxide|Zr(OH)<sub>4</sub>]],
[[Schwartz's reagent|C<sub>10</sub>H<sub>11</sub>ClZr]],
[[Zirconium propionate|Zr(CH<sub>3</sub>CH<sub>2</sub>COO)<sub>4</sub>]],
[[zirconium tungstate|Zr(WO<sub>4</sub>)<sub>2</sub>]],
[[Zirconium(II) hydride|ZrH<sub>2</sub>]],
[[Lead zirconate titanate|Pb(Zr<sub>''x''</sub>Ti<sub>1-''x''</sub>)O<sub>3</sub>]]

== Precautions ==
[[Image:Zirconium rod.jpg|thumb|right|Zirconium rod]]
Compounds containing zirconium are not noted for toxicity. The metal dust can ignite in air and should be regarded as a major fire and explosion hazard. Zirconium has no known [[biology|biological]] role.

==References==
*[http://periodic.lanl.gov/elements/40.html Los Alamos National Laboratory &ndash; Zirconium]
{{reflist|2}}

== External links ==
{{Commons|Zirconium}}
{{wiktionary|zirconium}}
*[http://www.webelements.com/webelements/elements/text/Zr/index.html WebElements.com &ndash; Zirconium]

[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Zirconium|*]]
[[Category:Pyrotechnic fuels]]

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[[af:Sirkonium]]
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