Argon (Ar)
noble-gasGas
標準原子量
39.948 u [39.792, 39.963]電子配置
[Ne] 3s2 3p6融点
-189.35 °C沸点
-185.85 °C密度
1.7837 kg/m³酸化数
0電気陰性度（Pauling）
データなし第1イオン化エネルギー
15.759612 eV発見年
1894原子半径
71 pm詳細
Argon is a colorless noble gas and the third most abundant gas in Earth’s atmosphere, after nitrogen and oxygen. Its closed-shell electron configuration makes it chemically very inert under ordinary conditions. Most terrestrial argon is ⁴⁰Ar, produced by the radioactive decay of ⁴⁰K in rocks. The element is valued mainly as a dense, nonreactive atmosphere for industrial, analytical, and lighting applications.
Argon is two and one half times as soluble in water as nitrogen, having about the same solubility as oxygen. Argon is colorless and odorless, both as a gas and liquid. Argon is considered to be a very inert gas and is not known to form true chemical compounds, as do krypton, xenon, and radon.
The name derives from the Greek argos for "lazy" or "inactive" because it does not combine with other elements. It was discovered in 1894 by the Scottish chemist William Ramsay and the English physicist Robert John Strutt (Lord Rayleigh) in liquefied air. Rayleigh's initial interest derived from a problem posed by the English physicist Henry Cavendish in 1785, i.e., when oxygen and nitrogen were removed from air, there was an unknown residual gas remaining.
Argon was discovered by Sir William Ramsay, a Scottish chemist, and Lord Rayleigh, an English chemist, in 1894. Argon makes up 0.93% of the earth's atmosphere, making it the third most abundant gas. Argon is obtained from the air as a byproduct of the production of oxygen and nitrogen.
From the Greek argos, inactive. Its presence in air was suspected by Cavendish in 1785, discovered by Lord Raleigh and Sir William Ramsay in 1894.
Pure argon is a monatomic gas at ordinary temperature and pressure, with no color, odor, or taste. It liquefies to a colorless liquid at cryogenic temperature and freezes to a transparent solid. In electrical discharges it emits a pale violet to lavender glow, depending on pressure and lamp conditions.
Argon is widely used as an inert shielding gas in arc welding, metal refining, and heat treatment, especially where nitrogen or oxygen would react with hot metals. It fills incandescent and some fluorescent lamps, provides inert atmospheres for crystal growth and semiconductor processing, and serves as a carrier or plasma gas in analytical instruments such as gas chromatographs and inductively coupled plasma spectrometers. Argon lasers have been used in medicine, research, and display technology, although many older uses have been replaced by other laser systems.
Argon is frequently used when an inert atmosphere is needed. It is used to fill incandescent and fluorescent light bulbs to prevent oxygen from corroding the hot filament. Argon is also used to form inert atmospheres for arc welding, growing semiconductor crystals and processes that require shielding from other atmospheric gases.
Once thought to be completely inert, argon is known to form at least one compound. The synthesis of argon fluorohydride (HArF) was reported by Leonid Khriachtchev, Mika Pettersson, Nino Runeberg, Jan Lundell and Markku Räsänen in August of 2000. Stable only at very low temperatures, argon fluorohydride begins to decompose once it warms above -246°C (-411°F). Because of this limitation, argon fluorohydride has no uses outside of basic scientific research.
It is used in electric light bulbs and in fluorescent tubes at a pressure of about 400 Pa. and in filling photo tubes, glow tubes, etc. Argon is also used as an inert gas shield for arc welding and cutting, as blanket for the production of titanium and other reactive elements, and as a protective atmosphere for growing silicon and germanium crystals.
Isotopes in Earth/Planetary Science
Argon’s chemically inert properties and three stable isotopes make it an ideal tracer of Earth processes [101] Noble Gases in Geochemistry and Cosmochemistry: Reviews in Mineralogy and Geochemistry, D. Porcelli, C. J. Ballentine, and R. Wieler (Eds.), p. 844, Mineralogical Society of America and the Geochemical Society, Washington, DC (2002)., [157] SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas. Argon, SAHRA – Sustainability of Semi-Arid Hydrology and Riparian Areas (2014), Feb. 24; http://web.sahra.arizona.edu/programs/isotopes/argon.html., [158] J. K. W. Lee. Chem. Geol.266, 104 (2009)., [159] F. M. Phillips, M. C. Castro. “Groundwater dating and residence-time measurements”, in Treatise on Geochemistry, J. I. Drever, H. D. Holland, and K. K. Turekian (Eds.), Pergamon Press, Oxford, New York (2003)., [160] T. Kobashi, J. P. Severinghaus, K. Kawamura. Geochim. Cosmochim. Acta.72, 4675 (2008)., [161] H. Sumino, K. Ikehata, A. Shimizu, K. Nagao, S. Nakada. J. Volcanol. Geotherm. Res.175, 189 (2008)., [162] D. R. Hilton, K. Hammerschmidt, G. Loock, H. Friedrichsen. Geochim. Cosmochim. Acta.57, 2819 (1993)., [163] B. P. Christensen, P. M. Holm, A. Jambon, J. R. Wilson. Chem. Geol.178, 127 (2001)., [164] H. H. Loosli, B. E. Lehmann, W. Balderer. Geochim. Cosmochim. Acta53, 1825 (1989)., [165] T. Torgersen, B. M. Kennedy, H. Hiyagon, K. Y. Chiou, J. H. Reynolds, W. B. Clarke. Earth Planet. Sci. Lett.92, 43 (1989)., [166] J. K. Böhlke. Pure Appl. Chem.86, 1421 (2014)., [167] P. R. Renne, K. A. Farley, T. A. Becker, W. D. Sharp. Earth Planet. Sci. Lett.188, 435 (2001).. Measurements and models of the isotope-amount ratio n(40Ar)/n(36Ar) can provide insights about the evolution of the atmosphere and orogenic (mountain-building) history of the Earth. The comparison of results from potassium-argon and n(40Ar)/n(39Ar) isotope-amount-ratio dating methods with results from other dating methods has been used to study temperature histories of rocks through differences in apparent ages caused by excess argon or partial argon gas loss. The isotope-amount ratio n(40Ar)/n(36Ar) of dissolved argon in groundwater can provide hydrologic information, such as rates of crustal degassing and relative groundwater age. 38Ar produced by cosmic-ray bombardment of rocks and soils at Earth’s surface can provide information about surface exposure history and erosion rate.
Isotopes in Geochronology
Argon isotopes are used to date rock samples, especially volcanic rocks, using two related techniques (Fig. IUPAC.18.1) [101] Noble Gases in Geochemistry and Cosmochemistry: Reviews in Mineralogy and Geochemistry, D. Porcelli, C. J. Ballentine, and R. Wieler (Eds.), p. 844, Mineralogical Society of America and the Geochemical Society, Washington, DC (2002)., [168] G. B. Dalrymple, M. A. Lanphere. Potassium-Argon Dating: Principles, Techniques and Applications to Geochronology, p. 258, Freeman, San Francisco (1969)., [169] I. McDougall, T. M. Harrison. Geochronology and Thermochronology by the 40Ar/39Ar Method, p. 212, Oxford University Press, Oxford (1999)., [170] United States Geological Survey. Periodic Table-Argon, U.S. Geological Survey (2014), Feb. 25; http://wwwrcamnl.wr.usgs.gov/isoig/period/ar_iig.html..
–The first technique is potassium-argon dating (K-Ar), which is based on the decay of radioactive 40K to stable 40Ar. By comparing the concentrations of potassium and 40Ar in a sample, it is possible to determine how long the sample has been accumulating radiogenic 40Ar to determine the “age” of the sample. The half-life of 40K is approximately 1.25×109 years, making this a useful tool for dating rocks range in age from about 106 to 109 years.
–A modification of the potassium-argon dating technique is the n(40Ar)/n(39Ar) isotope-amount-ratio technique, in which a sample is irradiated in a nuclear reactor to produce 39Ar from 39K. The isotope-amount ratio n(40Ar)/n(39Ar) is then determined, and from this, the approximate age of the rock can be calculated (Fig. IUPAC.18.2).
The study of 37Ar (half-life of 35 days), 39Ar (half-life of 268 years), and 40Ar concentrations in groundwater can provide information about the production and release of these isotopes from rocks and other sources into groundwater and the relative ages of different groundwaters [159] F. M. Phillips, M. C. Castro. “Groundwater dating and residence-time measurements”, in Treatise on Geochemistry, J. I. Drever, H. D. Holland, and K. K. Turekian (Eds.), Pergamon Press, Oxford, New York (2003)., [164] H. H. Loosli, B. E. Lehmann, W. Balderer. Geochim. Cosmochim. Acta53, 1825 (1989)., [165] T. Torgersen, B. M. Kennedy, H. Hiyagon, K. Y. Chiou, J. H. Reynolds, W. B. Clarke. Earth Planet. Sci. Lett.92, 43 (1989)., [171] B. E. Lehmann, R. Purtschert. Appl. Geochem.12, 727 (1997)., [172] H. Z. Loosli, B. E. Lehmann, W. M. Smethie, Jr. “Noble gas radioisotopes: 37Ar, 85Kr, 39Ar, 81Kr”, in Environmental Tracers in Subsurface Hydrology, P. G. Cook and A. L. Herczeg (Eds.), Kluwer, Boston (2000)., [173] R. Yokochi, N. C. Sturchio, R. Purtschert. Geochim. Cosmochim. Acta88, 19 (2012)..
Isotopes in Industry
38K (half-life of 7.6 min), which is produced by the reactions 38Ar (p, n) 38K and 40Ar (n, 3n) 38K, is a widely used blood-flow tracer. Because 38Ar is more expensive, 40Ar, which also offers many additional advantages as a target, is more commonly used to produce 38K for medical purposes [176] K. Nagatsu, A. Kubodera, K. Suzuki. Appl. Radiat. Isot.49, 1505 (1998)., [177] J. R. Mercer, M. J. M. Duke, S. A. McQuarrie. Appl. Radiat. Isot.52, 1413 (2000).. 41Ar (half-life of 1.82 h) is used as an industrial gas-flow tracer to help track the movement of gases because its inert properties, half-life, and gamma radiation make it well suited for this purpose [177] J. R. Mercer, M. J. M. Duke, S. A. McQuarrie. Appl. Radiat. Isot.52, 1413 (2000)..
Argon has no stable neutral compounds under ordinary conditions, and its chemistry is extremely limited compared with heavier noble gases. The best established neutral argon compound is argon fluorohydride, HArF, made in cryogenic matrices and stable only at very low temperature. Argon can form ions and weakly bound complexes in plasmas, mass spectrometers, and solids, including ArH⁺ and van der Waals adducts. Clathrate-like trapping of argon in cages is physical inclusion rather than normal valence chemistry.
See more information at the Argon compound page.
Argon is not chemically toxic and is nonflammable, but it is an asphyxiant because it can displace breathable air, especially in confined or low-lying spaces. Liquid argon can cause severe cold burns and can embrittle some materials. Gas released from cryogenic liquid expands strongly and may create oxygen-deficient atmospheres. High-pressure cylinders add mechanical and handling hazards.
Atmospheric argon is well mixed and chemically persistent because it reacts only under exceptional conditions. Natural ⁴⁰Ar accumulates from decay of ⁴⁰K within minerals and is released slowly by weathering, volcanism, and degassing. Argon has no known biological role and is not a greenhouse gas of practical concern, since it does not absorb strongly in the main thermal infrared bands under atmospheric conditions.
Commercial argon is obtained almost entirely by fractional distillation of liquefied air, usually as a coproduct of large oxygen and nitrogen plants. Supply is therefore tied to industrial gas infrastructure and to demand for bulk oxygen in steelmaking, chemicals, and other sectors. Ultra-high-purity grades require additional purification to remove oxygen, nitrogen, water, and hydrocarbons. Recycling is uncommon for general welding use but can be economical in closed or high-purity systems such as specialized metallurgy and semiconductor processing.
The gas is prepared by fractionation of liquid air because the atmosphere contains 0.94% argon. The atmosphere of Mars contains 1.6% of 40Ar and 5 ppm of 36Ar.
Argon is a significant cosmic noble gas, produced mainly in massive stars during oxygen and silicon burning and dispersed by supernovae. In the Solar System it occurs in planetary atmospheres, meteorites, and the solar wind, but its abundance varies strongly because noble gases are readily lost from small or warm bodies. Radiogenic ⁴⁰Ar is especially important in rocky planets and in potassium-argon geochronology.
- Argon’s name comes from the Greek word for inactive, reflecting its chemical inertness.
- Atmospheric argon is mostly radiogenic ⁴⁰Ar, not primordial ³⁶Ar.
- Argon is denser than air, so leaks can accumulate in pits and poorly ventilated spaces.
- Potassium-argon dating depends on the retention of ⁴⁰Ar produced inside minerals.
- Argon is often preferred over helium when a heavier, less thermally conductive inert gas is useful.
画像
性質
物理的性質
- 原子半径（経験値）
- 71 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 106 pm 全元素の共有結合半径を比較 →
- ファンデルワールス半径
- 188 pm 全元素のファンデルワールス半径を比較 →
- 密度
- 1.7837 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0242 L/mol
- 標準温度・圧力（STP）での相
- 気体 全元素の標準温度・圧力（STP）での相を比較 →
- 融点
- -189.35 °C 全元素の融点を比較 →
- 沸点
- -185.85 °C 全元素の沸点を比較 →
- 熱伝導率
- 0.018 W/(m·K) 全元素の熱伝導率を比較 →
- 比熱容量
- 0.52 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 20.786 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 面心立方構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Allen）
- 3.242
- 電子親和力
- -1 eV (負の値—この原子は電子を取り込まないと予測される)
- 第1イオン化エネルギー
- 15.759612 eV 全元素の第1イオン化エネルギーを比較 →
- 第2イオン化エネルギー
- 27.629765 eV 全元素の第2イオン化エネルギーを比較 →
- 第3イオン化エネルギー
- 40.73514 eV 全元素の第3イオン化エネルギーを比較 →
- 第4イオン化エネルギー
- 59.580205 eV 全元素の第4イオン化エネルギーを比較 →
- 第5イオン化エネルギー
- 74.840258 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- 0 全元素の酸化数を比較 →
- 価電子
- 8 全元素の価電子を比較 →
- 電子配置
- [Ne] 3s2 3p6
熱力学的性質
- 三重点（温度）
- -189.34 °C
- 三重点（圧力）
- 6.89e+4 Pa
- 臨界点（温度）
- -122.463 °C
- 臨界点（圧力）
- 4.863e+6 Pa
- 融解熱
- 0.01222988 eV 全元素の融解熱を比較 →
- 蒸発熱
- 0.06664248 eV 全元素の蒸発熱を比較 →
- 原子化熱
- 0 eV
原子核
- 陽子数
- 18 全元素の陽子数を比較 →
- 中性子数
- 22 全元素の中性子数を比較 →
- 既知の同位体
- 26 全元素の既知の同位体を比較 →
- 安定同位体
- 3 全元素の安定同位体を比較 →
- 最も安定な同位体
- Ar-40
- 発見年
- 1894
存在度
- 存在度（地殻）
- 3.5 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 0.45 mg/L 全元素の存在度（海洋）を比較 →
結晶構造
- 格子定数a
- 526 pm
電子構造
- 各電子殻の電子数
- 2, 8, 8 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-37-1 全元素のCAS登録番号を比較 →
- 項記号
- 1S0
- InChI
- InChI=1S/Ar
- InChI Key
- XKRFYHLGVUSROY-UHFFFAOYSA-N
電子配置 測定値
Ar: 3s² 3p⁶[Ne] 3s² 3p⁶1s² 2s² 2p⁶ 3s² 3p⁶原子モデル
同位体によって中性子数、質量、安定性は変わりますが、中性原子の電子配置は変わりません。
模式的な原子モデルです。実際の縮尺とは異なります。
原子の指紋
発光／吸収スペクトル
同位体分布
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 36 安定 | 35.967545105 ± 0.000000028 | 0.3336% | 安定 |
| 38 安定 | 37.96273211 ± 0.00000021 | 0.0629% | 安定 |
| 40 安定 | 39.9623831237 ± 0.0000000024 | 99.6035% | 安定 |
相／状態
理由: 沸点（-185.85 °C）より210.8 °C高い
模式図、実際の縮尺とは異なります
相転移点
相転移エネルギー
融点で1 molを融解させるのに必要なエネルギー
沸点で1 molを蒸発させるのに必要なエネルギー
密度
標準条件下
現在の温度Tにおいて理想気体の状態方程式で推定
詳細
原子スペクトル
全18件中10件を表示しています。 イオンの電荷の昇順で並べています。
スペクトル線データの収録状況 ?
| イオン | 電荷 | スペクトル線の総数 | 遷移確率 | 準位の表記 |
|---|---|---|---|---|
| Ar I | 0 | 461 | 428 | 429 |
| Ar II | +1 | 2858 | 307 | 2858 |
| Ar III | +2 | 509 | 80 | 509 |
| Ar IV | +3 | 256 | 42 | 256 |
| Ar V | +4 | 111 | 18 | 111 |
| Ar VI | +5 | 104 | 6 | 104 |
| Ar VII | +6 | 218 | 21 | 218 |
| Ar VIII | +7 | 141 | 27 | 141 |
| Ar IX | +8 | 178 | 2 | 178 |
| Ar X | +9 | 92 | 1 | 92 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Ar I | 0 | 504 |
| Ar II | +1 | 419 |
| Ar III | +2 | 125 |
| Ar IV | +3 | 58 |
| Ar V | +4 | 49 |
| Ar VI | +5 | 44 |
| Ar VII | +6 | 95 |
| Ar VIII | +7 | 72 |
| Ar IX | +8 | 98 |
| Ar X | +9 | 71 |
化合物
同位体 (3)
Naturally occurring argon is a mixture of three isotopes. Twelve other radioactive isotopes are known to exist.
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 36 安定 | 35.967545105 ± 0.000000028 | 0.3336% ± 0.0021% | 安定 | stable | |
| 38 安定 | 37.96273211 ± 0.00000021 | 0.0629% ± 0.0007% | 安定 | stable | |
| 40 安定 | 39.9623831237 ± 0.0000000024 | 99.6035% ± 0.0025% | 安定 | stable |
スペクトル線
全1065件中50件を表示しています。 初期設定では、強度の測定値があるスペクトル線のみを表示します。
| 波長（nm） | 強度 | 電離段階 | 種類 | 遷移 | 精度 | 出典 | |
|---|---|---|---|---|---|---|---|
| 458.989759 nm | 25704 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST | |
| 472.686807 nm | 23442 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2D* | 測定値 | NIST | |
| 696.543 nm | 10000 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<1/2>).4p 2[1/2] | 測定値 | NIST | |
| 706.72175 nm | 10000 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<1/2>).4p 2[3/2] | 測定値 | NIST | |
| 738.39801 nm | 10000 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<1/2>).4p 2[3/2] | 測定値 | NIST | |
| 440.098598 nm | 8710 | Ar II | emission | 3s2.3p4.(3P).3d 4D → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 501.716264 nm | 7413 | Ar II | emission | 3s2.3p4.(3P).3d 2D → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST | |
| 476.486444 nm | 2344 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2P* | 測定値 | NIST | |
| 460.956692 nm | 2291 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST | |
| 487.986345 nm | 2239 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2D* | 測定値 | NIST | |
| 727.29354 nm | 2000 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<1/2>).4p 2[1/2] | 測定値 | NIST | |
| 427.752786 nm | 1995 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2P* | 測定値 | NIST | |
| 434.806354 nm | 1995 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 480.602014 nm | 1820 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 454.505166 nm | 1738 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2P* | 測定値 | NIST | |
| 442.60008 nm | 1514 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 465.79009 nm | 1445 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2P* | 測定値 | NIST | |
| 473.590548 nm | 1000 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 714.7041 nm | 1000 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<1/2>).4p 2[3/2] | 測定値 | NIST | |
| 413.172327 nm | 891 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2P* | 測定値 | NIST | |
| 496.507942 nm | 891 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2D* | 測定値 | NIST | |
| 457.934934 nm | 871 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2S* | 測定値 | NIST | |
| 484.780955 nm | 832 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 437.988058 nm | 794 | Ar II | emission | 3s2.3p4.(3P).4p 2S* → 3s2.3p4.(3P).5s 2P | 測定値 | NIST | |
| 407.200431 nm | 708 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2D* | 測定値 | NIST | |
| 443.018862 nm | 661 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 448.181045 nm | 646 | Ar II | emission | 3s2.3p4.(3P).3d 2D → 3s2.3p4.(1D).4p 2D* | 測定値 | NIST | |
| 437.075295 nm | 617 | Ar II | emission | 3s2.3p4.(3P).3d 2D → 3s2.3p4.(1D).4p 2D* | 測定値 | NIST | |
| 433.119915 nm | 603 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 437.966649 nm | 550 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 611.492319 nm | 537 | Ar II | emission | 3s2.3p4.(1D).3d 2G → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST | |
| 410.391181 nm | 447 | Ar II | emission | 3s2.3p4.(3P).4p 4D* → 3s2.3p4.(3P).5s 4P | 測定値 | NIST | |
| 617.227751 nm | 407 | Ar II | emission | 3s2.3p4.(1D).3d 2G → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST | |
| 415.85907 nm | 400 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<3/2>).5p 2[3/2] | 測定値 | NIST | |
| 420.067472 nm | 400 | Ar I | emission | 3s2.3p5.(2P*<3/2>).4s 2[3/2]* → 3s2.3p5.(2P*<3/2>).5p 2[5/2] | 測定値 | NIST | |
| 506.203703 nm | 398 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 437.132854 nm | 355 | Ar II | emission | 3s2.3p4.(3P).3d 4D → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 500.93342 nm | 355 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 447.475916 nm | 347 | Ar II | emission | 3s2.3p4.(3P).3d 2D → 3s2.3p4.(1D).4p 2P* | 測定値 | NIST | |
| 422.815775 nm | 331 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 2D* | 測定値 | NIST | |
| 404.289342 nm | 288 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2D* | 測定値 | NIST | |
| 426.652661 nm | 288 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 488.904194 nm | 288 | Ar II | emission | 3s2.3p4.(3P).4s 2P → 3s2.3p4.(3P).4p 2P* | 測定値 | NIST | |
| 423.721956 nm | 269 | Ar II | emission | 3s2.3p4.(1D).4s 2D → 3s2.3p4.(1D).4p 2P* | 測定値 | NIST | |
| 664.369734 nm | 269 | Ar II | emission | 3s2.3p4.(3P).3d 4F → 3s2.3p4.(3P).4p 4D* | 測定値 | NIST | |
| 385.058079 nm | 263 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4S* | 測定値 | NIST | |
| 440.009637 nm | 257 | Ar II | emission | 3s2.3p4.(3P).3d 4D → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 443.099589 nm | 251 | Ar II | emission | 3s2.3p4.(3P).3d 4D → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 493.320891 nm | 251 | Ar II | emission | 3s2.3p4.(3P).4s 4P → 3s2.3p4.(3P).4p 4P* | 測定値 | NIST | |
| 514.17826 nm | 224 | Ar II | emission | 3s2.3p4.(3P).3d 2D → 3s2.3p4.(1D).4p 2F* | 測定値 | NIST |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 96 pm
- 共有結合半径（Pyykkö、二重結合）
- 107 pm
- 共有結合半径（Pyykkö、三重結合）
- 96 pm
ファンデルワールス半径
- Bondi
- 188 pm
- Alvarez
- 194 pm
- UFF
- 386.8 pm
- MM3
- 199 pm
原子半径と金属半径
- 原子半径（Rahm）
- 197 pm
番号付けの尺度
- Mendeleev
- 114
- Pettifor
- 3
- Glawe
- 3
電気陰性度の尺度
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 5
分極率と分散
- 双極子分極率
- 11.083 a.u.
- 双極子分極率（不確かさ）
- 0.007 a.u.
- C₆
- 64.2 Ha·Bohr6
- C₆ (Gould–Bučko)
- 67.4 Ha·Bohr6
化学親和力
- プロトン親和力
- 369.2 kJ/mol
- 気相塩基性
- 346.3 kJ/mol
希ガスの性質
相転移と同素体
| 融点 | 83.81 K |
| 沸点 | 87.3 K |
| 臨界点（温度） | 150.69 K |
| 臨界点（圧力） | 4.86 MPa |
| 三重点（温度） | 83.81 K |
| 三重点（圧力） | 68.89 kPa |
専門参考データ
遮蔽定数 (5)
| n | 軌道 | σ |
|---|---|---|
| 1 | s | 0.4925 |
| 2 | p | 3.9918 |
| 2 | s | 5.7696 |
| 3 | p | 11.2359 |
| 3 | s | 10.2432 |
同位体の崩壊形式 (46)
| 同位体 | モード | 強度 |
|---|---|---|
| 29 | 2p | 100% |
| 30 | 2p | 100% |
| 31 | B+ | 100% |
| 31 | B+p | 68.3% |
| 31 | 2p | 9% |
| 31 | B+pA | 0.4% |
| 31 | 3p | 0.1% |
| 31 | B+A | 0% |
| 31 | 2p | 0% |
| 32 | B+ | 100% |
X線散乱因子 (506)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0 |
| 10.1617 | — | 0 |
| 10.3261 | — | 0 |
| 10.4931 | — | 0 |
| 10.6628 | — | 0 |
| 10.8353 | — | 0 |
| 11.0106 | — | 0 |
| 11.1886 | — | 0 |
| 11.3696 | — | 0 |
| 11.5535 | — | 0 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
3.5 milligrams per kilogram
参考文献 (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
4.5×10-1 milligrams per liter
参考文献 (1)
Sources
Sources of this element.
The gas is prepared by fractionation of liquid air because the atmosphere contains 0.94% argon. The atmosphere of Mars contains 1.6% of 40Ar and 5 ppm of 36Ar.
参考文献 (1)
- [6] Argon https://periodic.lanl.gov/18.shtml
参考文献
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Argon.
The element property data was retrieved from publications.