This article pertains to the chemical element. For other uses, see argon (disambiguation).

18 chlorine ← argon → potassium Ne ↑ Ar ↓ Kr Periodic table - Extended periodic table
General
Name, symbol, number	argon, Ar, 18
Chemical series	noble gases
Group, period, block	18, 3, p
Appearance	colorless
Standard atomic weight	39.948(1) g·mol−1
Electron configuration	[Ne] 3s2 3p6
Electrons per shell	2, 8, 8
Physical properties
Phase	gas (At room temperature)
Density	(0 °C, 101. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity A period 3 element is one of the Chemical elements in the third row (or period) of the periodic table of the elements. See also Electron configuration The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties This page is about the physical properties of gas as a state of matter The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 325 kPa) 1. 784 g/L
Melting point	83. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 80 K (−189. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 35 °C, −308. The Celsius Temperature scale was previously known as the centigrade scale. 83 °F)
Boiling point	87. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 30 K (−185. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 85 °C, −302. The Celsius Temperature scale was previously known as the centigrade scale. 53 °F)
Triple point	83. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 In Thermodynamics, the triple point of a substance is the Temperature and Pressure at which three phases (for example Gas, Liquid 8058 K (-189°C), 69 kPa
Critical point	150. The Celsius Temperature scale was previously known as the centigrade scale. In Physical chemistry, Thermodynamics, Chemistry and Condensed matter physics, a critical point, also called a critical state 87 K, 4. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 898 MPa
Heat of fusion	1. The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 18 kJ·mol−1
Heat of vaporization	6. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required 43 kJ·mol−1
Specific heat capacity	(25 °C) 20. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 786 J·mol−1·K−1
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K   47 53 61 71 87
Atomic properties
Crystal structure	cubic face centered
Oxidation states	0
Electronegativity	no data (Pauling scale)
Ionization energies (more)	1st: 1520. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. The oxidation number of a central atom in a coordination compound is the charge that it would have if all the Ligands were removed along with the Electron pairs " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron These tables list the Ionization energy in kJ/mol necessary to remove one mole of Electrons from one mole of neutral gaseous Atoms (first energy respectively 6 kJ·mol−1
	2nd: 2665. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 8 kJ·mol−1
	3rd: 3931 kJ·mol−1
Atomic radius	71 pm
Atomic radius (calc. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth )	71 pm
Covalent radius	97 pm
Van der Waals radius	188 pm
Miscellaneous
Magnetic ordering	nonmagnetic
Thermal conductivity	(300 K) 17. The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. Van der Waals Volume The van der Waals volume, V, also called the atomic volume or molecular volume, is the atomic property most directly In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. 72x10-3  W·m−1·K−1
Speed of sound	(gas, 27 °C) 323 m/s
CAS registry number	7440–37–1
Selected isotopes
Main article: Isotopes of argon iso NA half-life DM DE (MeV) DP 36Ar 0. Sound is a vibration that travels through an elastic medium as a Wave. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to The main Isotopes of Argon ( Ar) found on Earth are 40Ar 36Ar and 38Ar Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide 337% 36Ar is stable with 18 neutrons 37Ar syn 35 d ε 0. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in A day (symbol d is a unit of Time equivalent to 24 Hours and the duration of a single Rotation of planet Earth with respect to the Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the 813 37Cl 38Ar 0. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and 063% 38Ar is stable with 20 neutrons 39Ar syn 269 y β- 0. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in To help compare Orders of magnitude of different times this page lists times between 109 Seconds (a gigasecond) and 1010 seconds (31 A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 565 39K 40Ar 99. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 600% 40Ar is stable with 22 neutrons 41Ar syn 109. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 34 min β- 2. A minute is a Unit of measurement of Time or of Angle. The minute is a unit of Time equal to 1/60th of an Hour or 60 49 41K 42Ar syn 32. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 9 y β- 0. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun 600 42K
References
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Argon (pronounced /ˈɑrgɒn/) is a chemical element designated by the symbol Ar. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Recommended values for many properties of the elements together with various references are collected on these data pages A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. Argon has atomic number 18 and is the third element in group 18 of the periodic table (noble gases). See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton The periodic table of the chemical elements is a tabular method of displaying the Chemical elements Although precursors to this table exist its invention is History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity Argon is present in the Earth's atmosphere at 0. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five 93%, making it the most abundant noble gas on Earth. Its full outer shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83. In Thermodynamics, the triple point of a substance is the Temperature and Pressure at which three phases (for example Gas, Liquid 8058 K is a defining fixed point in the International Temperature Scale of 1990. The International Temperature Scale of 1990 ( ITS-90) is an equipment calibration standard for making measurements on the Kelvin and

Characteristics

Argon has approximately the same solubility in water as oxygen gas and is 2. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. 5 times more soluble in water than nitrogen gas. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Argon is colorless, odorless, tasteless and nontoxic in both its liquid and gaseous forms. This page is about the physical properties of gas as a state of matter Argon is 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. History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity For example, the creation of argon hydrofluoride (HArF), a metastable compound of argon with fluorine and hydrogen, was reported by researchers at the University of Helsinki in 2000. Argon fluorohydride (HArF is the first known compound of the Chemical element Argon. Fluorine, fluorum meaning "to flow" is the Chemical element with the symbol F and Atomic number 9 Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 The University of Helsinki (Helsingin yliopisto Helsingfors universitet is a University located in Helsinki, Finland since 1829 but founded ^[1] Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of it are trapped in a lattice of the water molecules. A clathrate or clathrate compound or cage compound is a Chemical substance consisting of a lattice of one type of molecule trapping Water ( H2[[oxygen O]] H OH) is the most abundant Molecule on Earth 's surface composing of about 70% of the Earth's surface as ^[2] Also argon-containing ions and excited state complexes, such as ArH+ and ArF, respectively, are known to exist. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An excimer (originally short for excited dimer) is a short-lived dimeric or heterodimeric Molecule formed from two species at least one of which is in Theoretical calculations have shown several argon compounds that should be stable but for which no synthesis routes are currently known.

History

Argon (Greek meaning "inactive," in reference to its chemical inactivity)^[3][4][5] was suspected to be present in air by Henry Cavendish in 1785 but was not discovered until 1894 by Lord Rayleigh and Sir William Ramsay in Scotland in an experiment in which they removed all of the oxygen and nitrogen from a sample of air. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Henry Cavendish, FRS (10 October 1731 - 24 February 1810 was a British Scientist noted for his discovery of Hydrogen or what he called "inflammable John William Strutt 3rd Baron Rayleigh OM (12 November 1842 &ndash 30 June 1919 was an English Physicist who with William Ramsay, discovered Sir William Ramsay (2 October 1852 &ndash 23 July 1916 was a Scottish chemist who discovered the Noble gases and received the Nobel Prize in Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 ^[6][7] 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. ^[8] 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. ^[9]

Occurrence

An argon & mercury vapour discharge tube.

Argon constitutes 0. 934% by volume and 1. 29% by mass of the Earth's atmosphere, and air is the primary raw material used by industry to produce purified argon products. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Argon is isolated from air by fractionation, most commonly by cryogenic fractional distillation, a process that also produces purified nitrogen, oxygen, neon, krypton and xenon. Fractionation is a Separation process in which a certain quantity of a Mixture (solid liquid solute or suspension is divided up in a number of smaller quantities Cryogenics is often used incorrectly to refer to Cryonics, cryopreserving humans or animals Fractional distillation is the separation of a mixture into its component parts or fractions such as in separating Chemical compounds by their Boiling point by heating Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. ^[10]

The Martian atmosphere in contrast contains 1. 6% of argon-40 and 5 ppm of argon-36. "Parts-per" notation is used especially in Science and Engineering, to denote Ratios (relative proportions in measured quantities particularly The Mariner spaceprobe fly-by of the 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. The Mariner program was a program conducted by the American space agency NASA that launched a series of robotic interplanetary probes A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is In 2005, the Huygens probe also discovered the presence of argon-40 on Titan, the largest moon of Saturn. Cassini–Huygens is a joint NASA / ESA / ASI Robotic spacecraft mission currently studying the planet Saturn and its TemplateInfobox Planet.--> Titan (ˈtaɪtən, or as ^[11]

Isotopes

Main article: Isotopes of argon

The main isotopes of argon found on Earth are ⁴⁰Ar (99. The main Isotopes of Argon ( Ar) found on Earth are 40Ar 36Ar and 38Ar Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides 6%), ³⁶Ar (0. 34%), and ³⁸Ar (0. 06%). Naturally occurring ⁴⁰K with a half-life of 1. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Half-Life (computer-game page here It's already listed in the disambiguation page 25×10⁹ years, decays to stable ⁴⁰Ar (11. 2%) by electron capture and positron emission, and also to stable ⁴⁰Ca (88. Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the Positron emission is a type of Beta decay, sometimes referred to as " beta plus " (&beta+ 8%) via beta decay. In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted These properties and ratios are used to determine the age of rocks. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere ^[12]

In the Earth's atmosphere, ³⁹Ar is made by cosmic ray activity, primarily with ⁴⁰Ar. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " For the 1962 Bruce Conner film see Cosmic Ray (film Cosmic rays are energetic particles originating from space that impinge on In the subsurface environment, it is also produced through neutron capture by ³⁹K or alpha emission by calcium. Neutron capture is a kind of Nuclear reaction in which an Atomic nucleus collides with one or more Neutrons and they merge to form a heavier nucleus Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 ³⁷Ar is created from the decay of ⁴⁰Ca as a result of subsurface nuclear explosions. Nuclear weapons tests are experiments carried out to determine the effectiveness yield and explosive capability of Nuclear weapons Throughout the twentieth century most nations It has a half-life of 35 days. ^[12]

Compounds

Argon’s complete octet of electrons indicates full s and p subshells. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J 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 compounds were formed by researchers at the University of Helsinki. The University of Helsinki (Helsingin yliopisto Helsingfors universitet is a University located in Helsinki, Finland since 1829 but founded By shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride, argon hydrofluoride (HArF) was formed. Argon fluorohydride (HArF is the first known compound of the Chemical element Argon. ^[13] It is stable up to 40 kelvins (−233 °C). The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale.

The discovery of argon difluoride (ArF₂) was announced in 2003, but this is unconfirmed and most probably incorrect.

See also:H₂-Ar

A small piece of rapidly melting argon ice. A van der Waals molecule is a stable cluster consisting of two or more Molecules held together by Van der Waals forces or by Hydrogen bonds.

Production

Industrial

Argon is produced industrially by the partial distillation of liquid air, a process that separates liquid nitrogen, which boils at 77. Distillation is a method of separating Mixtures based on differences in their volatilities in a boiling liquid mixture Liquid Air was the brand name of an unusual Automobile produced by a joint American / English concern between 1899 and 1902 Liquid nitrogen (liquid density at the Triple point is 0707 g/mL is the liquid produced industrially in large quantities by Fractional distillation of 3K, from argon, which boils at 87. 3 K and oxygen, which boils only at 90. 2 K. About 700 000 tons of argon are produced worldwide every year. ^[14]

In radioactive decays

Argon-40, the most abundant isotope of argon, is produced by the decay of potassium-40 with a half-life of 1. The main Isotopes of Argon ( Ar) found on Earth are 40Ar 36Ar and 38Ar Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 26e+9 years by electron capture or positron emission. Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the Positron emission is a type of Beta decay, sometimes referred to as " beta plus " (&beta+

Potassium-argon dating

Main article: Potassium-argon dating

Applications

Canisters containing argon gas for use in extinguishing fire without damaging server equipment

There are several different reasons why argon is used in particular applications:

• An inert gas is needed. Potassium-argon dating or K-Ar dating is a Radiometric dating method used in Geochronology and Archeology. Fire is the heat and light energy released during a Chemical reaction, in particular a combustion reaction. In English to be inert is to be in a state of doing little or nothing In particular, argon is the cheapest alternative when diatomic nitrogen is not sufficiently inert. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14
• Low thermal conductivity is required. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat.
• The electronic properties (ionization and/or the emission spectrum) are necessary.

Other noble gases would probably work as well in most of these applications, but argon is by far the cheapest. History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity Argon is inexpensive since it is a byproduct of the production of liquid oxygen and liquid nitrogen, both of which are used on a large industrial scale. Liquid nitrogen (liquid density at the Triple point is 0707 g/mL is the liquid produced industrially in large quantities by Fractional distillation of The other noble gases (except helium) are produced this way as well, but argon is the most plentiful since it has the highest concentration in the atmosphere. The bulk of argon applications arise simply because it is inert and relatively cheap. Argon is used:

• As a fill gas in incandescent lighting, because argon will not react with the filament of light bulbs even at high temperatures. The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general An electrical filament is a thread of Metal, usually Tungsten, which is used to convert Electricity into light in Incandescent light bulbs (as developed The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general
• As an inert gas shield in many forms of welding, including metal inert gas welding and tungsten inert gas welding. Welding is a fabrication process that joins materials usually Metals or Thermoplastics by causing coalescence. Gas metal arc welding (GMAW, sometimes referred to by its subtypes metal inert gas (MIG welding or metal active gas (MAG welding, is a semi-automatic or automatic Gas tungsten arc welding ( GTAW) also known as tungsten inert gas (TIG welding, is an Arc welding process that uses a nonconsumable Tungsten For metal inert gas welding Argon is often mixed with CO₂. Gas metal arc welding (GMAW, sometimes referred to by its subtypes metal inert gas (MIG welding or metal active gas (MAG welding, is a semi-automatic or automatic
• For extinguishing fires where damage to equipment is to be avoided (see photo).
• As the gas of choice for the plasma used in ICP spectroscopy. An inductively coupled plasma ( ICP) is a type of plasma source in which the Energy is supplied by Electrical currents which are produced by Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ
• As a non-reactive blanket in the processing of titanium and other reactive elements. Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22
• As a protective atmosphere for growing silicon and germanium crystals, and in partial pressure heat treat furnaces. Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Germanium (dʒɚˈmeɪniəm is a Chemical element with the symbol Ge and Atomic number 32 In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating
• By museum conservators to protect old materials or documents, which are prone to gradual oxidation in the presence of air. ^[15]
• To keep open bottles of wine from oxidizing, and in a number of dispensing units and keeper cap systems.
• In winemaking to top off barrels, displacing oxygen and thus preventing the wine from turning to vinegar during the aging process.
• In the pharmaceutical industry to top off bottles of intravenous drug preparations (for example intravenous paracetamol), again displacing oxygen and therefore prolonging the drug's shelf-life. Intravenous therapy or IV therapy is the giving of Liquid substances directly into a Vein. Paracetamol ( INN) (ˌpærəˈsiːtəmɒl -ˈsɛtə- or acetaminophen ( USAN) is a widely-used Analgesic and Antipyretic Medication Shelf life is that length of time that Food, drink Medicine and other perishable items are given before they are considered unsuitable for sale or
• Used to cool the seeker head of the US Air Force version of the AIM-9 Sidewinder missile, and other missiles that use cooled thermal seeker heads. The AIM-9 Sidewinder is a heat-seeking, short-range Air-to-air missile carried by Fighter aircraft and recently certain gunship helicopters The gas is stored at high pressure, and the expansion of the gas cools the seeker. The AIM-9 Sidewinder is a heat-seeking, short-range Air-to-air missile carried by Fighter aircraft and recently certain gunship helicopters ^[16]
• As an atmosphere in graphite electric furnaces, to keep graphite from oxidizing.

The next most common reason for using argon is its low thermal conductivity. It is used for thermal insulation in energy efficient windows. The term thermal insulation can refer to materials used to reduce the rate of Heat transfer, or the methods and processes used to reduce heat transfer GlassWindowjpg|thumb|right|190px|A stained glass panel depicting Biblical scenes at a historic church in Scotland]] A window is an opening ^[17] Argon is also used in technical scuba diving to inflate a dry suit, because it is inert and has low thermal conductivity. Scuba diving is swimming underwater, or taking part in another activity while using a Scuba set. A dry suit or drysuit provides Thermal insulation or passive thermal protection to the wearer while immersed in water and is worn by divers, It is also used to replace nitrogen in the breathing or decompression mix, to reduce the onset of nitrogen narcosis, or to speed the elimination of dissolved nitrogen from the blood. Nitrogen narcosis or inert gas narcosis is a reversible alteration in Consciousness in scuba divers at depth See Argox (scuba). Argox is the informal name for a Scuba diving Breathing gas consisting of Argon and Oxygen.

Argon is also used for the specific way it ionizes and emits light. It is used in plasma globes and calorimetry in experimental particle physics. Plasma lamps (also variously plasma globes balls domes spheres or orbs are Novelty items which were most popular in the 1980s In Particle physics, a calorimeter is an experimental apparatus that measures the Energy of particles. Particle physics is a branch of Physics that studies the elementary constituents of Matter and Radiation, and the interactions between them Blue argon lasers are used in surgery to weld arteries, destroy tumors, and to correct eye defects. ^[18] In microelectronics, argon ions are used for sputtering. Sputtering is a process whereby Atoms are Ejected from a solid target material due to bombardment of the target by energetic Ions It is commonly used for

Finally, there are a number of miscellaneous uses. Argon-39, with a half life of 269 years, has been used for a number of applications, primarily ice core and ground water dating. An ice core is a Core sample from the accumulation of snow and ice over many years that have re-crystallized and have trapped air bubbles from previous time periods Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations Also, potassium-argon dating is used in dating igneous rocks. Potassium-argon dating or K-Ar dating is a Radiometric dating method used in Geochronology and Archeology. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock

Cryosurgery procedures such as cryoablation use liquified argon to destroy cancer cells. Cryosurgery (cryotherapy is the application of extreme cold to destroy abnormal or diseased tissue Cryoablation is a process that uses cold energy (cryo to kill tissue (ablation Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled In surgery it is used in a procedure called "argon enhanced coagulation" which is a form of argon plasma beam electrosurgery. Electrosurgery is the application of a high-frequency electric current to human (or other animal tissue as a means to remove Lesions, Staunch bleeding or cut tissue 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. An air embolism, or more generally gas embolism, is a medical condition caused by Gas bubbles in the bloodstream ( embolism in a medical context refers to ^[19]

Potential hazards

Although Argon is non-toxic, it does not satisfy the body's need for oxygen and is a simple asphyxiant, and, in confined spaces, is known to result in death due to asphyxiation. A recent multiple fatality in Florida (USA) highlights the dangers of Argon tank leakage in confined spaces, and, emphasizes the need for its proper use, storage and handling. ^[20]

References

Further reading

• Los Alamos National Laboratory – Argon
• USGS Periodic Table - Argon
• Emsley, J. , Nature’s Building Blocks; Oxford University Press: Oxford, NY, 2001; pp. 35-39.
• Brown, T. L. ; Bursten, B. E. ; LeMay, H. E. , In Chemistry: The Central Science, 10th ed. ; Challice, J. ; Draper, P. ; Folchetti, N. et al. ; Eds. ; Pearson Education, Inc. : Upper Saddle River, NJ, 2006; pp. 276 and 289.
• Triple point temperature: 83. 8058 K - Preston-Thomas, H. (1990). "The International Temperature Scale of 1990 (ITS-90)". Metrologia 27: 3–10. doi:10.1088/0026-1394/27/1/002. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
• Triple point pressure: 69 kPa - (2005) "Section 4, Properties of the Elements and Inorganic Compounds; Melting, boiling, triple, and critical temperatures of the elements", CRC Handbook of Chemistry and Physics, 85th edition, Boca Raton, Florida: CRC Press.  

External links

• WebElements.com – Argon
• Diving applications: Why Argon?
• Argon Ar Properties, Uses, Applications
• Computational Chemistry Wiki