「Argon」の版間の差分

提供：脳科学辞典
ナビゲーションに移動 検索に移動
(ページの作成:「{{Use dmy dates|date=June 2013}} {{About|the chemical element}} {{Distinguish|Argonne (disambiguation)}} {{pp-move-indef}} {{good article}} {{Infobox argon}} '''Argon'''...」)
 
細 (wj:アルゴンへの転送ページ)
 
1行目: 1行目:
{{Use dmy dates|date=June 2013}}
#redirect[[wj:アルゴン]]
{{About|the chemical element}}
{{Distinguish|Argonne (disambiguation)}}
{{pp-move-indef}}
{{good article}}
{{Infobox argon}}
 
'''Argon''' is a [[chemical element]] with  symbol '''Ar''' and [[atomic number]] 18. It is in group 18 of the [[periodic table]] and is a [[noble gas]]. Argon is the third most common gas in the [[Earth's atmosphere]], at 0.93% (9,300 ppm), making it approximately 23.8 times as abundant as the next most common atmospheric gas, [[carbon dioxide]] (390 ppm), and more than 500 times as abundant as the next most common noble gas, [[neon]] (18 ppm). Nearly all of this argon is [[radiogenic]] [[argon-40]] derived from the [[Radioactive decay|decay]] of [[potassium-40]] in the Earth's crust. In the universe, [[argon-36]] is by far the most common argon [[isotope]], being the preferred argon isotope produced by stellar [[nucleosynthesis]] in [[supernova]]s.
 
The name "argon" is derived from the [[Greek language|Greek]] word '''αργον''', neuter singular form of '''αργος''' meaning "lazy" or "inactive", as a reference to the fact that the element undergoes almost no chemical reactions. The complete [[octet rule|octet]] (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its [[triple point]] temperature of 83.8058 [[Kelvin|K]] is a defining fixed point in the [[International Temperature Scale of 1990]].
 
Argon is produced industrially by the [[fractional distillation]] of [[liquid air]]. Argon is mostly used as an [[inert]] [[shielding gas]] in welding and other high-temperature industrial processes where ordinarily non-reactive substances become reactive; for example, an argon atmosphere is used in [[graphite]] electric furnaces to prevent the graphite from burning. Argon gas also has uses in [[Incandescent light bulb|incandescent]] and [[fluorescent lighting]], and other types of gas discharge tubes. Argon makes a distinctive [[Ion laser#Argon laser|blue-green gas laser]].
 
==Characteristics==
[[File:Argon ice 1.jpg|upright|thumb|left|A small piece of rapidly melting solid argon.]]
Argon has approximately the same [[solubility]] in water as oxygen, and is 2.5 times more soluble in water than [[nitrogen]]. Argon is colorless, odorless, and nontoxic as a solid, liquid, and gas. Argon is chemically [[inert]] under most conditions and forms no confirmed stable compounds at room temperature.
 
Although argon is a [[noble gas]], it has been found to have the capability of forming some compounds. For example, the creation of [[argon fluorohydride]] (HArF), a marginally stable compound of argon with [[fluorine]] and [[hydrogen]], was reported by researchers at the [[University of Helsinki]] in 2000.<ref name="findarticles-harf">
{{cite news
|last=Perkins |first=S.
|date=26 August 2000
|title=HArF! Argon's not so noble after all – researchers make argon fluorohydride
|url=http://www.sciencenews.org/view/generic/id/795/description/HArF_Argons_not_so_noble_after_all
|work=Science News
}}</ref> Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form [[clathrates]] with [[water (molecule)|water]] when atoms of it are trapped in a lattice of the water molecules.<ref>
{{cite journal
|last=Belosludov |first=V. R.
|coauthors=''et al.''
|year=2006
|title=Microscopic model of clathrate compounds
|journal=[[Journal of Physics: Conference Series]]
|volume=29 |pages=1
|doi = 10.1088/1742-6596/29/1/001
|bibcode = 2006JPhCS..29....1B }}</ref> Argon-containing [[ions]] and [[exciplex|excited state complexes]], such as {{chem|ArH|+}} and ArF, respectively, are known to exist. Theoretical calculations have predicted several argon compounds that should be stable,<ref>
{{cite journal
|last1=Cohen |first1=A.
|last2=Lundell |first2=J.
|last3=Gerber |first3=R. B.
|year=2003
|title=First compounds with argon–carbon and argon–silicon chemical bonds
|journal=[[Journal of Chemical Physics]]
|volume=119 |pages = 6415
|doi=10.1063/1.1613631
|bibcode = 2003JChPh.119.6415C
|issue=13 }}</ref> but for which no synthesis routes are currently known.
 
==History==
[[Image:Isolation of Argon.png|thumb|left|upright|[[John William Strutt, 3rd Baron Rayleigh|Lord Rayleigh]]'s method for the isolation of argon, based on an experiment of [[Henry Cavendish]]'s. The gases are contained in a test-tube (A) standing over a large quantity of weak [[alkali]] (B), and the current is conveyed in wires insulated by U-shaped glass tubes (CC) passing through the liquid and round the mouth of the test-tube. The inner platinum ends (DD) of the wire receive a current from a battery of five [[Grove cell]]s and a [[Ruhmkorff coil]] of medium size.]]
''Argon'' (αργον, neuter singular form of αργος, [[Greek language|Greek]] meaning "inactive", in reference to its chemical inactivity)<ref name="lazyone1">
{{cite book
|last = Hiebert |first = E. N.
|year = 1963
|chapter = In Noble-Gas Compounds
|editor = Hyman, H. H.
|title = Historical Remarks on the Discovery of Argon: The First Noble Gas
|publisher = [[University of Chicago Press]]
|pages = 3–20
}}</ref><ref name="lazyone2">
{{cite book
|last=Travers |first = M. W.
|year=1928
|title=The Discovery of the Rare Gases
|pages=1–7
|publisher=Edward Arnold & Co.
}}</ref> was suspected to be present in air by [[Henry Cavendish]] in 1785 but was not isolated until 1894 by [[John William Strutt, 3rd Baron Rayleigh|Lord Rayleigh]] and Sir [[William Ramsay]] in Scotland in an experiment in which they removed all of the [[oxygen]], [[carbon dioxide]], [[water]] and [[nitrogen]] from a sample of clean air.<ref>
{{cite journal
|author=[[Lord Rayleigh]]; [[William Ramsay|Ramsay, William]]
|year=1894–1895
|title=Argon, a New Constituent of the Atmosphere
|journal=[[Proceedings of the Royal Society of London]]
|volume=57 |issue=1 |pages=265–287
|doi=10.1098/rspl.1894.0149
|jstor=115394
}}</ref><ref name="lazyone3">
{{cite journal
|author=Lord Rayleigh; Ramsay, William
|year = 1895
|title = VI. Argon: A New Constituent of the Atmosphere
|journal = [[Philosophical Transactions of the Royal Society of London A]]
|volume = 186 |pages = 187
|doi= 10.1098/rsta.1895.0006
|jstor=90645
|bibcode = 1895RSPTA.186..187R }}</ref><ref>
{{cite web
|last=Ramsay |first=W.
|year=1904
|title=Nobel Lecture
|url=http://nobelprize.org/nobel_prizes/chemistry/laureates/1904/ramsay-lecture.html
|publisher=[[The Nobel Foundation]]
}}</ref> They had determined that nitrogen produced from chemical compounds was one-half percent lighter than nitrogen from the atmosphere. The difference seemed insignificant, but it was important enough to attract their attention for many months. They concluded that there was another gas in the air mixed in with the nitrogen.<ref>
{{cite news
|date=3 March 1895
|title=About Argon, the Inert; The New Element Supposedly Found in the Atmosphere
|url=http://query.nytimes.com/gst/abstract.html?res=9B04E3D61139E033A25750C0A9659C94649ED7CF
|work=[[The New York Times]]
|accessdate = 2009-02-01
}}</ref> Argon was also encountered in 1882 through independent research of H. F. Newall and W.N. Hartley. Each observed new lines in the color spectrum of air but were unable to identify the element responsible for the lines. Argon became the first member of the noble gases to be discovered. The symbol for argon is now "Ar", but up until 1957 it was "A".<ref>
{{cite web
|last=Holden |first=N. E.
|date=12 March 2004
|title=History of the Origin of the Chemical Elements and Their Discoverers
|url=http://www.nndc.bnl.gov/content/elements.html
|publisher=[[National Nuclear Data Center]]
}}</ref>
 
== Occurrence ==
Argon constitutes 0.934% by volume and 1.28% by mass of the [[Earth's atmosphere]], and air is the primary raw material used by industry to produce purified argon products. Argon is isolated from air by fractionation, most commonly by [[cryogenics|cryogenic]] [[fractional distillation]], a process that also produces purified [[nitrogen]], [[oxygen]], [[neon]], [[krypton]] and [[xenon]].<ref>
{{cite web
|title=Argon, Ar
|url=http://elements.etacude.com/Ar.php
|publisher=Etacude.com
|accessdate=2007-03-08
}}</ref>
 
== Isotopes ==
{{Main|Isotopes of argon}}
 
The main [[isotope]]s of argon found on Earth are {{chem|40|Ar}} (99.6%), {{chem|36|Ar}} (0.34%), and {{chem|38|Ar}} (0.06%). Naturally occurring {{chem|40|[[potassium|K]]}} with a [[half-life]] of 1.25{{e|9}} years, decays to stable {{chem|40|Ar}} (11.2%) by [[electron capture]] or [[positron emission]], and also to stable {{chem|40|Ca}} (88.8%) via [[beta decay]]. These properties and ratios are used to determine the age of [[Rock (geology)|rocks]] by the method of [[K-Ar dating]].<ref name=iso>
{{cite web
|url=http://www.geoberg.de/text/geology/07011601.php
|title=40Ar/39Ar dating and errors
|accessdate=2007-03-07
|archiveurl = http://web.archive.org/web/20070509023017/http://www.geoberg.de/text/geology/07011601.php
|archivedate = May 9, 2007
}}</ref>
 
In the Earth's atmosphere, {{chem|39|Ar}} is made by [[cosmic ray]] activity, primarily with {{chem|40|Ar}}. In the subsurface environment, it is also produced through [[neutron capture]] by {{chem|39|K}} or [[alpha decay|alpha emission]] by [[calcium]]. {{chem|37|Ar}} is created from the neutron [[spallation]] of {{chem|40|Ca}} as a result of subsurface [[nuclear testing|nuclear explosions]]. It has a half-life of 35 days.<ref name=iso/>
 
Argon is notable in that its isotopic composition varies greatly between different locations in the [[solar system]]. Where the major source of argon is the decay of [[potassium-40|{{chem|40|K}}]] in rocks, {{chem|40|Ar}} will be the dominant isotope, as it is on Earth. Argon produced directly by [[stellar nucleosynthesis]], in contrast, is dominated by the [[alpha process]] nuclide, {{chem|36|Ar}}. Correspondingly, solar argon contains 84.6% {{chem|36|Ar}} based on [[solar wind]] measurements.<ref>
{{cite journal
|last=Lodders |first=K.
|year = 2008
|title=The solar argon abundance
|journal=[[Astrophysical Journal]]
|volume=674 |pages=607
|arxiv=0710.4523
|doi=10.1086/524725
|bibcode=2008ApJ...674..607L
}}</ref>  [[Primordial nuclide|Primordial]] {{chem|36|Ar}} has an abundance of only 31.5 ppmv (= 9340 ppmv x 0.337%), comparable to that of neon (18.18 ppmv).
The [[Atmosphere of Mars|Martian atmosphere]] contains 1.6% of {{chem|40|Ar}} and 5&nbsp;[[Parts per million|ppm]] of {{chem|36|Ar}}. The [[Mariner program|Mariner]] space probe fly-by of the [[planet]] [[Mercury (planet)|Mercury]] in 1973 found that Mercury has a very thin atmosphere with 70% argon, believed to result from releases of the gas as a decay product from radioactive materials on the planet. In 2005, the ''[[Cassini–Huygens|Huygens]]'' probe also discovered the presence of {{chem|40|Ar}} on [[Titan (moon)|Titan]], the largest moon of [[Saturn]].<ref>
{{cite web
|url=http://www.esa.int/esaCP/SEMHB881Y3E_index_0.html
|title= Seeing, touching and smelling the extraordinarily Earth-like world of Titan
|date=2005-01-21
|publisher=European Space Agency
}}</ref>
Similarly, the ratio of the three isotopes <sup>36</sup>Ar: <sup>38</sup>Ar: <sup>40</sup>Ar in the atmospheres of the outer planets is measured to be 8400: 1600: 1<ref>Cameron, A. G. W., "Elemental and Isotopic Abundances of the Volatile Elements in the Outer Planets" (Article published in the Space Science Reviews special issue on 'Outer Solar System Exploration - An Overview', ed. by J. E. Long and D. G. Rea.)  Journal: Space Science Reviews, Volume 14, Issue 3-4, pp. 392-400 (1973).</ref>
 
The predominance of [[radiogenic]] {{chem|40|Ar}} is responsible for the fact that the [[standard atomic weight]] of terrestrial argon is greater than that of the next element, [[potassium]]. This was puzzling at the time when argon was discovered, since [[Dmitri Mendeleev|Mendeleev]] had placed the elements in his [[periodic table]] in order of atomic weight, although the inertness of argon implies that it must be placed before the reactive alkali metal potassium. [[Henry Moseley]] later solved this problem by showing that the periodic table is actually arranged in order of [[atomic number]]. (See [[History of the periodic table]]).
 
==Compounds==
{{See also|Van der Waals molecule}}
[[File:Argon-fluorohydride-3D-vdW.png|200px|thumb|right|[[Space-filling model]] of [[argon fluorohydride]].]]
Argon's complete octet of [[electrons]] indicates full s and p subshells. This full outer energy level makes argon very stable and extremely resistant to bonding with other elements. Before 1962, argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized. In August 2000, the first argon compound was formed by researchers at the [[University of Helsinki]]. By shining ultraviolet light onto frozen argon containing a small amount of [[hydrogen fluoride]] with [[caesium iodide]],<ref>{{cite book|author = Kean, Sam|chapter = Chemistry Way, Way Below Zero|title = The Disappearing Spoon|year = 2011|publisher=Black Bay Books}}</ref> [[argon fluorohydride]] (HArF) was formed.<ref name="findarticles-harf" /><ref>
{{cite web
|url=http://pubs.acs.org/cen/80th/noblegases.html
|title=The Noble Gases
|author=[[Neil Bartlett (chemist)|Bartlett, Neil]]
|publisher=Chemical & Engineering News (2003)
}}</ref> It is stable up to 40&nbsp;[[kelvin]] (−233&nbsp;°C). The [[metastable]] {{chem|ArCF|2|2+}} dication, which is valence [[isoelectronicity|isoelectronic]] with [[carbonyl fluoride]], was observed in 2010.<ref>
{{cite journal
|last=Lockyear |first = Jessica F.
|coauthors=''et al.''
|year=2010
|title=Generation of the ArCF<sub>2</sub><sup>2+</sup> Dication
|journal=[[Journal of Physical Chemistry Letters]]
|volume=1 |page=358
|doi=10.1021/jz900274p
}}</ref>
 
==Production==
===Industrial===
Argon is produced industrially by the [[fractional distillation]] of [[liquid air]] in a [[cryogenic]] [[air separation]] unit; a process that separates [[liquid nitrogen]], which boils at 77.3&nbsp;K, from argon, which boils at 87.3&nbsp;K, and [[liquid oxygen]], which boils at 90.2&nbsp;K. About 700,000 [[tonne]]s of argon are produced worldwide every year.<ref>
{{cite web
|url=http://environmentalchemistry.com/yogi/periodic/Ar.html
|title=Periodic Table of Elements: Argon – Ar
|publisher=Environmentalchemistry.com
|accessdate=2008-09-12
}}</ref>
 
===In radioactive decays===
[[Isotopes of argon|<sup>40</sup>Ar]], the most abundant [[isotope]] of argon, is produced by the decay of <sup>40</sup>[[potassium|K]] with a half-life of 1.25{{e|9}} years by [[electron capture]] or [[positron emission]]. Because of this, it is used in [[potassium-argon dating]] to determine the age of rocks.
 
==Applications==
[[Image:Argon.jpg|thumb|left|180px|Cylinders containing argon gas for use in extinguishing [[fire]] without damaging server equipment]]
There are several different reasons argon is used in particular applications:
* An [[inert]] gas is needed. In particular, argon is the cheapest alternative when [[nitrogen]] is not sufficiently inert.
* Low [[thermal conductivity]] is required.
* The electronic properties (ionization and/or the emission spectrum) are necessary.
 
Other [[noble gas]]es would probably work as well in most of these applications, but argon is by far the cheapest. Argon is inexpensive since it is a byproduct of the production of [[liquid oxygen]] and [[liquid nitrogen]] from a [[cryogenic]] [[air separation]] unit, both of which are used on a large industrial scale. The other noble gases (except [[helium]]) are produced this way as well, but argon is the most plentiful by far, since it has a much higher concentration in the atmosphere. The bulk of argon applications arise simply because it is inert and relatively cheap.
 
===Industrial processes===
Argon is used in some high-temperature industrial processes, where ordinarily non-reactive substances become reactive. For example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning.
 
For some of these processes, the presence of nitrogen or oxygen gases might cause defects within the material. Argon is used in various types of [[arc welding]] such as [[gas metal arc welding]] and [[gas tungsten arc welding]], as well as in the processing of [[titanium]] and other reactive elements. An argon atmosphere is also used for growing crystals of [[silicon]] and [[germanium]].
 
{{See also|shielding gas}}
Argon is an [[asphyxiant gas|asphyxiant]] in the poultry industry, either for mass culling following disease outbreaks, or as a means of slaughter more humane than the electric bath. Argon's relatively high density causes it to remain close to the ground during gassing. Its non-reactive nature makes it suitable in a food product, and since it replaces oxygen within the dead bird, argon also enhances shelf life.<ref>
{{cite news
|last=Fletcher |first=D. L.
|title=Slaughter Technology
|url=http://ps.fass.org/cgi/reprint/78/2/277.pdf
|work=Symposium: Recent Advances in Poultry Slaughter Technology
|accessdate=2010-01-01
}}</ref>
 
Argon is sometimes used for extinguishing fires where damage to equipment is to be avoided.
 
===Scientific research===
Liquid argon is used as the target for direct [[dark matter]] searches. The interaction of a hypothetical [[Weakly interacting massive particles|WIMP]] particle with the argon nucleus produces [[scintillation (physics)|scintillation]] light that is detected by [[photomultiplier tubes]]. Two-phase detectors also use argon gas to detect the ionized electrons produced during the WIMP-nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation lightyield (~ 51 photons / keV<ref>
{{cite journal
|author1= Gastler
|coauthors=''et al.''
|year= 010
|title=Measurement of scintillation efficiency for nuclear recoils in liquid argon
|doi= 10.1103/PhysRevC.85.065811
|journal= Physical Review C
|volume= 85
|issue= 6
|arxiv=1004.0373
}}</ref>), is transparent to its own scintillation light, and is relatively easy to purify. Compared to [[xenon]], argon is cheaper and has a distinct scintillation time profile which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic gamma-ray background is larger due to {{chem|39|Ar}} contamination, unless one uses underground argon sources with a low level of radioactivity.{{clarify|reason = what are these sources and why do they have lower radioactivity??|date=June 2013}} Dark matter detectors currently operating with liquid argon include WArP, [[ArDM]], microCLEAN and DEAP-I.
 
===Preservative===
[[File:CsCrystals.JPG|thumb|A sample of [[caesium]] is packed under argon to avoid reactions with air]]
Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the [[E numbers|European food additive code]] of ''E938''). Aerial oxidation, hydrolysis, and other chemical reactions which degrade the products are retarded or prevented entirely. Bottles of high-purity chemicals and certain pharmaceutical products are available in sealed bottles or ampoules packed in argon. In wine making, argon is used to top-off barrels to avoid the aerial oxidation of [[ethanol]] to [[acetic acid]] during the aging process.
 
Argon is also available in [[aerosol]]-type cans, which may be used to preserve compounds such as [[varnish]], [[polyurethane]], paint, etc. for storage after opening.<ref>Zawalick, Steven Scott "Method for preserving an oxygen sensitive liquid product" {{US patent|6629402}} Issue date: October 7, 2003</ref>
 
Since 2002, the American [[National Archives]] stores important national documents such as the [[United States Declaration of Independence|Declaration of Independence]] and the [[United States Constitution|Constitution]] within argon-filled cases to retard their degradation. Using argon reduces gas leakage, compared with the helium used in the preceding five decades.<ref>
{{cite web
|url=http://www.archives.gov/press/press-kits/charters.html#pressrelaese1
|title=Schedule for Renovation of the National Archives Building
|accessdate=2009-07-07
}}</ref>
 
===Laboratory equipment===
[[Image:Glovebox.jpg|thumb|[[Glovebox]]es are often filled with argon, which recirculates over scrubbers to maintain an [[oxygen]]-, [[nitrogen]]-, and moisture-free atmosphere]]
{{See also|Air-free technique}}
 
Argon may be used as the [[inert gas]] within [[Schlenk line]]s and [[glovebox]]es. The use of argon over comparatively less expensive nitrogen is preferred where nitrogen may react with the experimental reagents or apparatus.
 
Argon may be used as the carrier gas in [[gas chromatography]] and in [[electrospray ionization mass spectrometry]]; it is the gas of choice for the plasma used in [[Inductively coupled plasma|ICP]] [[spectroscopy]]. Argon is preferred for the sputter coating of specimens for [[scanning electron microscopy]]. Argon gas is also commonly used for [[sputter deposition]] of thin films as in [[microelectronics]] and for [[microfabrication|wafer cleaning in microfabrication]].
 
===Medical use===
[[Cryosurgery]] procedures such as [[cryoablation]] use liquefied argon to destroy [[cancer]] cells. In surgery it is used in a procedure called "argon enhanced coagulation" which is a form of argon plasma beam [[electrosurgery]]. The procedure carries a risk of producing [[gas embolism]] in the patient and has resulted in the death of one person via this type of accident.<ref>
{{cite web
|url=http://www.mdsr.ecri.org/summary/detail.aspx?doc_id=8248
|title= Fatal Gas Embolism Caused by Overpressurization during Laparoscopic Use of Argon Enhanced Coagulation
|date=1994-06-24
|publisher=MDSR
}}</ref> Blue argon lasers are used in surgery to weld arteries, destroy tumors, and to correct eye defects.<ref>
{{cite web
|url=http://www.spie.org/Conferences/Programs/06/pw/BiOSAbstracts.pdf|format=pdf
|title=Tissue Optics, Laser-Tissue Interaction, and Tissue Engineering
|accessdate=2007-03-08
|last=Fujimoto |first=James
|coauthors=Rox Anderson, R.
|year=2006
|publisher=Biomedical Optics
|pages=77–88
}}</ref> It has also been used experimentally to replace nitrogen in the breathing or decompression mix, to speed the elimination of dissolved nitrogen from the blood.<ref>
{{cite journal
|author=Pilmanis Andrew A, Balldin UI, Webb James T, Krause KM
|title=Staged decompression to 3.5 psi using argon-oxygen and 100% oxygen breathing mixtures
|journal=Aviation, Space, Environmental Medicine
|volume=74 |issue=12 |pages=1243–50
|year=2003
|pmid=14692466
}}</ref> See [[Argox (breathing gas)|Argox]].
 
===Lighting===
[[File:ArTube.jpg|thumb|left|upright|Argon [[gas-discharge lamp]] forming the symbol for argon "Ar". Small amounts of [[mercury (element)|mercury]] are sometimes added to argon to produce an [[Electric blue (color)|electric blue]] color, as in this picture.]]
 
[[Incandescent light]]s are filled with argon, to preserve the [[electrical filament|filaments]] at high temperature from oxidation. It is used for the specific way it ionizes and emits light, such as in [[plasma globe]]s and [[Calorimeter (particle physics)|calorimetry]] in experimental [[particle physics]]. [[Gas-discharge lamp]]s filled with argon provide blue light. Argon is also used for the creation of blue and green laser light.
 
===Miscellaneous uses===
Argon is used for [[thermal insulation]] in [[Insulated glazing|energy efficient windows]].<ref>
{{cite web
|url=http://www.finehomebuilding.com/how-to/articles/understanding-energy-efficient-windows.aspx
|title=Energy-Efficient Windows
|accessdate=2009-08-01
|publisher=FineHomebuilding.com
}}</ref> Argon is also used in technical [[scuba diving]] to inflate a [[dry suit]], because it is inert and has low thermal conductivity.<ref name=IEEE2008>
{{cite journal
|author=Nuckols ML, Giblo J, Wood-Putnam JL.
|title=Thermal Characteristics of Diving Garments When Using Argon as a Suit Inflation Gas
|journal=Proceedings of the Oceans 08 MTS/IEEE Quebec, Canada Meeting
|publisher=MTS/IEEE
|date=September 15–18, 2008
|url=http://archive.rubicon-foundation.org/7962
|accessdate=2009-03-02
}}</ref>
Argon is being used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket ([[VASIMR]]).
Compressed argon gas is allowed to expand, to cool the seeker heads of the [[AIM-9 Sidewinder]] missile, and other missiles that use cooled thermal seeker heads. The gas is [[AIM-9 Sidewinder#Design| stored at high pressure]].<ref>
{{cite web
|url = http://home.wanadoo.nl/tcc/rnlaf/aim9.html
|title = Description of Aim-9 Operation
|accessdate = 2009-02-01
|publisher = planken.org
| archiveurl= http://web.archive.org/web/20081222025556/http://home.wanadoo.nl/tcc/rnlaf/aim9.html| archivedate= 22 December 2008 <!--DASHBot-->| deadurl= no}}</ref>
 
Argon-39, with a half-life of 269 years, has been used for a number of applications, primarily [[ice core]] and [[ground water]] dating. Also, [[potassium-argon dating]] is used in dating [[igneous rock]]s.
 
==Safety==
Although argon is non-toxic, it is 38% [[density|denser]] than air and is therefore considered a dangerous [[asphyxiant gas|asphyxiant]] in closed areas. It is also difficult to detect because it is colorless, odorless, and tasteless. A 1994 incident in which a man was [[asphyxia]]ted after entering an argon filled section of oil pipe under construction in [[Alaska]] highlights the dangers of argon tank leakage in confined spaces, and emphasizes the need for proper use, storage and handling.<ref>
{{cite web
|author = Alaska FACE Investigation 94AK012
|url = http://www.cdc.gov/niosh/face/stateface/ak/94ak012.html
|title = Welder's Helper Asphyxiated in Argon-Inerted Pipe – Alaska (FACE AK-94-012)
|publisher = State of Alaska Department of Public Health|date = 1994-06-23
|accessdate = 2011-01-29
}}</ref>
 
==See also==
*[[Industrial gas]]
 
{{Subject bar
|book1=Argon
|book2=Period 3 elements
|book3=Noble gases
|book4=Chemical elements (sorted&nbsp;alphabetically)
|book5=Chemical elements (sorted by number)
|portal=Chemistry
|commons=y
|wikt=y
|wikt-search=argon
|v=y
|v-search=Argon atom
|b=y
|b-search=Wikijunior:The Elements/Argon
}}
 
==References==
{{Reflist|colwidth=30em}}
 
==Further reading==
* Emsley, J., Nature's Building Blocks; Oxford University Press: Oxford, NY, 2001; pp.&nbsp;35–39.
* Brown, T. L.; Bursten, B. E.; LeMay, H. E., In ''Chemistry: The Central Science'', 10th ed.; Challice, J.; .; Folchetti, N. et al.; Eds.; Pearson Education, Inc.: Upper Saddle River, NJ, 2006; pp.&nbsp;276 and 289.
* Triple point temperature: 83.8058 K – {{cite journal
|first=H. |last=Preston-Thomas
|title=The International Temperature Scale of 1990 (ITS-90)
|journal=[[Metrologia]]
|volume=27 |pages=3–10
|year=1990
|url=http://www.bipm.org/en/publications/its-90.html
|doi=10.1088/0026-1394/27/1/002
|bibcode = 1990Metro..27....3P }}
* Triple point pressure: 69 kPa – {{cite book
|title=CRC Handbook of Chemistry and Physics
|edition=85th
|publisher=[[CRC Press]]
|year=2005
|location=Boca Raton, Florida
|chapter=Section 4, Properties of the Elements and Inorganic Compounds; Melting, boiling, triple, and critical temperatures of the elements
}}
 
==External links==
* [http://www.periodicvideos.com/videos/018.htm Silicon] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* [http://wwwrcamnl.wr.usgs.gov/isoig/period/ar_iig.html USGS Periodic Table – Argon]
* Diving applications: [http://www.decompression.org/maiken/Why_Argon.htm Why Argon?]
 
{{Compact periodic table}}
 
[[Category:Chemical elements]]
[[Category:Noble gases]]
[[Category:Argon| ]]
 
{{Link GA|zh}}
{{Link FA|de}}

2014年11月6日 (木) 08:53時点における最新版

転送先:

「https://bsd.neuroinf.jp/w/index.php?title=Argon&oldid=28361」から取得