Europium (Eu)
lanthanideSolid
標準原子量
151.964 u電子配置
[Xe] 6s2 4f7融点
821.85 °C沸点
1528.85 °C密度
5240 kg/m³酸化数
0, +2, +3電気陰性度（Pauling）
データなし第1イオン化エネルギー
5.670385 eV発見年
1896原子半径
185 pm詳細
Europium is a lanthanide rare-earth metal with atomic number 63. It is chemically notable for the relative stability of both Eu³⁺ and Eu²⁺, a contrast to most lanthanides, which are dominated by the +3 state. This redox flexibility controls much of its mineral behavior and its optical technology. Europium is best known for intense, narrow luminescence from Eu³⁺ and Eu²⁺ ions in solid hosts, especially in phosphors and security materials.
As with other rare-earth metals, except for lanthanum, europium ignites in air at about 150 to 180°C. Europium is about as hard as lead and is quite ductile. It is the most reactive of the rare-earth metals, quickly oxidizing in air. It resembles calcium in its reaction with water. Bastnasite and monazite are the principal ores containing europium.
The name derives from the continent of Europe. It was separated from the mineral samaria in magnesium- samarium nitrate by the French chemist Eugène-Anatole Demarçay in 1896. It was also first isolated by Demarçay in 1901.
Europium was discovered by Eugène-Antole Demarçay, a French chemist, in 1896. Demarçay suspected that samples of a recently discovered element, samarium, were contaminated with an unknown element. He was able to produce reasonably pure europium in 1901. Today, europium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements.
Named after Europe. In 1890 Boisbaudran obtained basic fractions from samarium-gadolinium concentrates which had spark spectral lines not accounted for by samarium or gadolinium. These lines subsequently have been shown to belong to europium. The discovery of europium is generally credited to Demarcay, who separated the rare earth in reasonably pure form in 1901. The pure metal was not isolated until recent years.
Pure europium is a soft, silvery metal that tarnishes rapidly in air and can darken as oxide and hydroxide layers form. It is among the more reactive lanthanide metals and is usually stored under inert gas or oil to limit oxidation.
Europium is used chiefly as an activator ion in luminescent materials. Eu³⁺ gives red emission in many oxide and vanadate phosphors, while Eu²⁺ can give blue, green, or other emissions depending on the host lattice. These phosphors have been important in color television tubes, fluorescent lamps, light-emitting diodes, displays, and anti-counterfeiting inks. Europium-doped materials are also used as optical probes in analytical assays, taking advantage of sharp emission lines and long-lived excited states.
Europium is the most reactive of the rare earth elements. There are no commercial applications for europium metal, although it has been used to dope some types of plastics to make lasers. Since it is a good absorber of neutrons, europium is being studied for use in nuclear reactors.
Europium oxide (Eu2O3), one of europium's compounds, is widely used as a red phosphor in television sets and as an activator for yttrium-based phosphors.
Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years.
Isotopes in Geochronology
For more than 40 years, weapons-grade plutonium was manufactured by the Krasnoyarsk Mining and Chemical Combine in the now closed town of Krasnoyarsk Krai, Russia, using single-pass uranium-graphite production reactors [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002).. Water from the Yenisei River was used for heat removal from the reactor core. Radioactively contaminated water was discharged into the Yenisei River and was a primary source of contamination of bottom sediments and floodland for hundreds of kilometers down gradient from the Krasnoyarsk Mining and Chemical Combine. In 2002, radioactive contamination of the bottom sediments and floodlands was composed primarily of 137Cs, 152Eu, 154Eu, and 60Co [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002).. The decrease in the isotope-amount ratio n(154Eu)/n(152Eu) down the depth profiles (Fig. IUPAC.63.1) enables one to determine the age of bottom sediments and floodlands of the Yenisei River and calculate their average formation rates [447] Z. G. Gritchenko, Y. V. Kuznetsov, V. K. Legin, V. N. Strukov. Radiochemistry44, 199 (2002)..
Isotopes in Industry
Europium isotopes have been used in nuclear-control applications because they are good neutron absorbers [448] C. R. Hammond. “The elements”, in CRC Handbook of Chemistry and Physics, C. Press, Taylor & Francis Group (1998).. 152Eu (with a half-life of 13.5 years), which is produced by 151Eu via the neutron capture reaction 151Eu (n, γ) 152Eu, and 154Eu (with a half-life of 8.59 years) are used as reference sources for calibration in gamma ray spectroscopy (Fig. IUPAC.63.2) [449] K. V. Vimalnatha, M. K. Dasb, M. Ananthakrishnana, N. Ramamoorthy. Appl. Radiat. Isot.62, 17 (2005)..
Isotopes Used as a Source of Radioactive Isotope(s)
Reactions on 153Eu can produce the therapeutic radionuclide 153Sm (with a half-life of about 1.9 days) via fast neutron irradiation 153Eu (n, p) 153Sm [451] M. Al-Abyad, I. Spahn, S. Sudár, M. Morsy, M. N. H. Comsan, J. Csikai, S. M. Qaim, H. H. Coenen. Appl. Radiat. Isot.64, 717 (2006)..
Europium chemistry is dominated by ionic compounds of Eu³⁺, but Eu²⁺ compounds are unusually accessible for a lanthanide and resemble alkaline-earth compounds in size and behavior. Europium(III) oxide, Eu₂O₃, is a common source and phosphor precursor. Europium(II) oxide, EuO, is a ferromagnetic semiconductor studied in solid-state physics. Halides such as europium(III) chloride, EuCl₃, and europium(II) chloride, EuCl₂, illustrate the two main oxidation states. Complexes of Eu³⁺ with organic ligands are widely used for luminescence studies.
See more information at the Europium compound page.
Europium metal presents a fire and chemical hazard because finely divided material can oxidize readily and reacts with moisture and acids to release hydrogen, H₂. Soluble europium salts are not known to have a biological role and should be treated as toxicologically incompletely characterized heavy-metal compounds. Dusts and aerosols are the main practical exposure concern in laboratories and phosphor manufacture. Natural europium is only weakly radioactive through long-lived ¹⁵¹Eu.
Europium occurs dispersed in rare-earth minerals rather than as native metal. It is typically present in monazite, bastnäsite, xenotime, and related deposits, and it follows other trivalent rare earths during weathering and sediment transport. Its ability to exist as Eu²⁺ under reducing geological conditions produces europium anomalies in rocks and minerals, which are useful tracers of magmatic and crustal processes. It has no known essential biological function.
Europium is produced as a separated rare earth from mineral concentrates, not mined as a primary element. Its separation is helped by the distinctive Eu²⁺/Eu³⁺ redox chemistry, but high purity still requires solvent extraction or ion-exchange processing. Demand has historically been tied to red phosphors for lamps and displays; changes in lighting technology and improved phosphor efficiency have reduced some consumption. Recycling from spent fluorescent lamps and display phosphors is technically possible, but collection, contamination, and changing waste streams limit broad recovery. Supply is linked to the wider rare-earth industry and to by-product recovery decisions.
Europium has been identified spectroscopically in the sun and certain stars. Seventeen isotopes are now recognized. Europium isotopes are good neutron absorbers and are being studied for use in nuclear control applications.
Europium is a rare element in the universe. Its stable isotopes are made mainly by neutron-capture nucleosynthesis, with the rapid r-process especially important. Because its spectral lines can be measured in old stars, europium is often used by astronomers as a tracer of r-process enrichment. In planetary materials it is lithophile and usually remains in oxide and silicate phases rather than metallic cores.
- Europium is one of the few lanthanides that commonly forms stable divalent compounds.
- Eu²⁺ can substitute for Ca²⁺ or Sr²⁺ in many phosphor host lattices.
- Europium anomalies help identify plagioclase fractionation in igneous rocks.
- The red emission of Eu³⁺ is extremely narrow compared with many organic dyes.
- EuO becomes ferromagnetic at low temperature.
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性質
物理的性質
- 原子半径（経験値）
- 185 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 198 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
- 233 pm 全元素のファンデルワールス半径を比較 →
- 密度
- 5240 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0289 L/mol
- 標準温度・圧力（STP）での相
- 固体 全元素の標準温度・圧力（STP）での相を比較 →
- 融点
- 821.85 °C 全元素の融点を比較 →
- 沸点
- 1528.85 °C 全元素の沸点を比較 →
- 熱伝導率
- 13.9 W/(m·K) 全元素の熱伝導率を比較 →
- 比熱容量
- 0.182 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 27.66 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 体心立方構造 全元素の結晶構造を比較 →
化学的性質
- 電子親和力
- 0.116 eV
- 第1イオン化エネルギー
- 5.670385 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
- 11.240039 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
- 24.840086 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
- 42.940148 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
- 63.200218 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- 0, +2, +3 全元素の酸化数を比較 →
- 価電子
- 3 全元素の価電子を比較 →
- 電子配置
- [Xe] 6s2 4f7
熱力学的性質
- 融解熱
- 0.09535161 eV 全元素の融解熱を比較 →
- 蒸発熱
- 1.824118 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 1.886304 eV
- 原子化熱
- 1.886304 eV
- 原子化エンタルピー
- 1.838628 eV
原子核
- 陽子数
- 63 全元素の陽子数を比較 →
- 中性子数
- 88 全元素の中性子数を比較 →
- 既知の同位体
- 41 全元素の既知の同位体を比較 →
- 安定同位体
- 0 全元素の安定同位体を比較 →
- 最も安定な同位体
- Eu-151
- 発見年
- 1896
存在度
- 存在度（地殻）
- 2 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 1.3 × 10−7 mg/L 全元素の存在度（海洋）を比較 →
結晶構造
- 格子定数a
- 461 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 25, 8, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-53-1 全元素のCAS登録番号を比較 →
- 項記号
- 8S°7/2
- InChI
- InChI=1S/Eu
- InChI Key
- OGPBJKLSAFTDLK-UHFFFAOYSA-N
電子配置 測定値
Eu: 4f⁷ 6s²[Xe] 4f⁷ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁷ 6s²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
安定同位体はありません。
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 153 放射性 | 152.921238 ± 0.0000018 | 52.1900% | 550 Py |
| 134 放射性 | 133.9464 ± 0.00032 | データなし | 500 ms |
| 169 放射性 | 168.961717 ± 0.000537 | データなし | 420 ms |
| 133 放射性 | 132.94929 ± 0.00032 | データなし | 200 ms |
| 168 放射性 | 167.957863 ± 0.000429 | データなし | 200 ms |
相／状態
理由: 融点（821.85 °C）より796.9 °C低い
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
昇華点で1 molを昇華させるのに必要なエネルギー
密度
標準条件下
標準条件下
原子スペクトル
全63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 |
|---|---|---|---|---|
| Eu I | 0 | 350 | 152 | 343 |
| Eu II | +1 | 218 | 13 | 13 |
| Eu III | +2 | 229 | 0 | 0 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Eu I | 0 | 592 |
| Eu II | +1 | 163 |
| Eu III | +2 | 118 |
| Eu IV | +3 | 13 |
| Eu V | +4 | 2 |
| Eu VI | +5 | 2 |
| Eu VII | +6 | 2 |
| Eu VIII | +7 | 2 |
| Eu IX | +8 | 2 |
| Eu X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +2 | 6 | データなし | 117 pm |
| +2 | 7 | データなし | 120 pm |
| +2 | 8 | データなし | 125 pm |
| +2 | 9 | データなし | 130 pm |
| +2 | 10 | データなし | 135 pm |
| +3 | 6 | データなし | 94.69999999999999 pm |
| +3 | 7 | データなし | 101 pm |
| +3 | 8 | データなし | 106.60000000000001 pm |
| +3 | 9 | データなし | 112.00000000000001 pm |
化合物
同位体 (5)
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 153 放射性 | 152.921238 ± 0.0000018 | 52.1900% ± 0.0600% | 550 Py | IS =52.19±0.6% | |
| 134 放射性 | 133.9464 ± 0.00032 | データなし | 500 ms | β+ =100%β+p =? | |
| 169 放射性 | 168.961717 ± 0.000537 | データなし | 420 ms | β- ? | |
| 133 放射性 | 132.94929 ± 0.00032 | データなし | 200 ms | β+ ?β+p ? | |
| 168 放射性 | 167.957863 ± 0.000429 | データなし | 200 ms | β- =100%β-n ? |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 168 pm
- 共有結合半径（Pyykkö、二重結合）
- 134 pm
ファンデルワールス半径
- Alvarez
- 287 pm
- UFF
- 349.3 pm
- MM3
- 294 pm
原子半径と金属半径
- 原子半径（Rahm）
- 280 pm
番号付けの尺度
- Mendeleev
- 25
- Pettifor
- 18
- Glawe
- 17
電気陰性度の尺度
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 3
- Robles–Bartolotti
- 2
分極率と分散
- 双極子分極率
- 184 a.u.
- 双極子分極率（不確かさ）
- 20 a.u.
- C₆ (Gould–Bučko)
- 2940 Ha·Bohr6
ミーデマパラメータ
- ミーデマモル体積
- 19.97 cm3/mol
- ミーデマ電子密度
- 2
供給リスクと経済性
- 生産集中度
- 97
- 相対供給リスク
- 10
- 埋蔵量の分布
- 50
- 政治的安定性（最大生産国）
- 24
- 政治的安定性（最大埋蔵国）
- 24
相転移と同素体
| 融点 | 1095.15 K |
| 沸点 | 1802.15 K |
酸化数の分類
専門参考データ
遮蔽定数 (13)
| n | 軌道 | σ |
|---|---|---|
| 1 | s | 1.2391 |
| 2 | p | 4.282 |
| 2 | s | 16.5292 |
| 3 | d | 13.7472 |
| 3 | p | 19.716 |
| 3 | s | 20.1318 |
| 4 | d | 34.0592 |
| 4 | f | 38.68 |
| 4 | p | 31.1252 |
| 4 | s | 30.132 |
結晶半径の詳細 (9)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 2 | VI | 131 | ||
| 2 | VII | 134 | ||
| 2 | VIII | 139 | ||
| 2 | IX | 144 | ||
| 2 | X | 149 | ||
| 3 | VI | 108.7 | from r^3 vs V plots, | |
| 3 | VII | 115 | ||
| 3 | VIII | 120.6 | from r^3 vs V plots, | |
| 3 | IX | 126 | from r^3 vs V plots, |
同位体の崩壊形式 (63)
| 同位体 | モード | 強度 |
|---|---|---|
| 130 | p | 100% |
| 130 | B+ | — |
| 130 | B+p | — |
| 131 | p | 89% |
| 131 | B+ | — |
| 131 | B+p | — |
| 132 | B+ | — |
| 132 | B+p | — |
| 132 | p | 0% |
| 133 | B+ | — |
X線散乱因子 (514)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.18583 |
| 10.1617 | — | 0.19489 |
| 10.3261 | — | 0.20439 |
| 10.4931 | — | 0.21435 |
| 10.6628 | — | 0.22479 |
| 10.8353 | — | 0.23529 |
| 11.0106 | — | 0.24598 |
| 11.1886 | — | 0.25716 |
| 11.3696 | — | 0.26817 |
| 11.5535 | — | 0.27854 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.0 milligrams per kilogram
参考文献 (1)
- [5] Europium https://education.jlab.org/itselemental/ele063.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.3×10-7 milligrams per liter
参考文献 (1)
- [5] Europium https://education.jlab.org/itselemental/ele063.html
Sources
Sources of this element.
Europium has been identified spectroscopically in the sun and certain stars. Seventeen isotopes are now recognized. Europium isotopes are good neutron absorbers and are being studied for use in nuclear control applications.
参考文献 (1)
- [6] Europium https://periodic.lanl.gov/63.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Europium is now prepared by mixing Eu2O3 with a 10%-excess of lanthanum metal and heating the mixture in a tantalum crucible under high vacuum. The element is collected as a silvery-white metallic deposit on the walls of the crucible.
参考文献 (1)
- [6] Europium https://periodic.lanl.gov/63.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 Europium.
The element property data was retrieved from publications.