Gadolinium (Gd)
lanthanideSolid
標準原子量
157.25 u電子配置
[Xe] 6s2 4f7 5d1融点
1312.85 °C沸点
3272.85 °C密度
7900 kg/m³酸化数
0, +1, +2, +3電気陰性度（Pauling）
1.2第1イオン化エネルギー
6.1498 eV発見年
1886原子半径
180 pm詳細
Gadolinium is a silvery lanthanide metal and one of the middle rare-earth elements. Its chemistry is dominated by the +3 oxidation state, but its seven unpaired 4f electrons give it unusually strong magnetic behavior for a rare-earth element. Natural gadolinium is a mixture of stable isotopes, with ¹⁵²Gd very long-lived and weakly radioactive. The element is technologically important in magnetic materials, neutron absorption, phosphors, and medical contrast agents.
As with other related rare-earth metals, gadolinium is silvery white, has a metallic luster, and is malleable and ductile. At room temperature, gadolinium crystallizes in the hexagonal, close-packed alpha form. Upon heating to 1235°C, alpha gadolinium transforms into the beta form, which has a body-centered cubic structure.
The metal is relatively stable in dry air, but tarnishes in moist air and forms a loosely adhering oxide film which falls off and exposes more surface to oxidation. The metal reacts slowly with water and is soluble in dilute acid.
Gadolinium has the highest thermal neutron capture cross-section of any known element (49,000 barns).
The name derives from the mineral gadolinite, in which it was found, and that had been named for the Finnish rare earth chemist Johan Gadolin. Gadolinium was discovered by the Swiss chemist Jean-Charles Galissard de Marignac in 1886, who produced a white oxide in a samarskite mineral. In 1886, the French chemist Paul-Emile Lecoq de Boisbaudran gave the name gadolinium.
Spectroscopic evidence for the existence of gadolinium was first observed by the Swiss chemist Jean Charles Galissard de Marignac in the minerals didymia and gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10) in 1880. Today, gadolinium is primarily obtained from the minerals monazite ((Ce, La, Th, Nd, Y)PO4) and bastnasite ((Ce,La,Y)CO3F).
From gadolinite, a mineral named for Gadolin, a Finnish chemist. The rare earth metal is obtained from the mineral gadolinite. Gadolinia, the oxide of gadolinium, was separated by Marignac in 1880 and Lecoq de Boisbaudran independently isolated it from Mosander's yttria in 1886.
Pure gadolinium is a soft, bright, silvery-white metal when freshly cut. It tarnishes in air and can form a darker oxide surface. At ordinary pressure it is ferromagnetic below about 20 °C, close enough to room temperature that modest temperature changes strongly affect its magnetism.
Gadolinium is used where high magnetic moment or high neutron-capture ability is valuable. Gadolinium compounds are used in some magnetic resonance imaging contrast agents, where chelation is essential to control toxicity. Gadolinium oxide is used in phosphors and scintillators, and gadolinium gallium garnet has served as a substrate and optical material. Gadolinium is also used in control materials and burnable neutron absorbers in some nuclear reactors, often as gadolinium oxide mixed into fuel.
Gadolinium has the greatest ability to capture thermal neutrons of all known elements and can be used as control rods for nuclear reactors. Unfortunately, the two isotopes best suited for neutron capture, gadolinium-155 and gadolinium-157, are present in gadolinium in small amounts. As a result, gadolinium control rods quickly lose their effectiveness.
Gadolinium can be combined with yttrium to form garnets that have applications in microwave technology. Gadolinium can be alloyed with iron, chromium and other metals to improve their workability and their resistance to high temperatures and oxidation. Gadolinium compounds are used to make phosphors for color televisions.
Gadolinium yttrium garnets are used in microwave applications and gadolinium compounds are used as phosphors in color television sets.
The metal has unusual superconductive properties. As little as 1 percent gadolinium improves the workability and resistance of iron, chromium, and related alloys to high temperatures and oxidation.
Gadolinium ethyl sulfate has extremely low noise characteristics and may find use in duplicating the performance of amplifiers, such as the maser.
The metal is ferromagnetic. Gadolinium is unique for its high magnetic movement and for its special Curie temperature (above which ferromagnetism vanishes) lying just at room temperature, meaning it could be used as a magnetic component that can sense hot and cold.
Isotopes in Earth/Planetary Science
The lunar surface is continuously exposed to cosmic radiation, and the interaction between planetary material and cosmic rays produces secondary neutrons. The neutron flux can be investigated using the large neutron capture cross sections of 149Sm, 155Gd, and 157Gd. For example, 157Gd will absorb neutrons and be converted to 158Gd. On a cross plot of n(158Gd)/n(160Gd) isotope-amount ratio and n(157Gd)/n(160Gd) isotope-amount ratio (Fig. IUPAC.64.1), values will move from the lower right corner to the upper left corner of the cross plot with increasing time or increasing flux.
Isotopes in Medicine
The addition of 157Gd to Neutron Capture Therapy (NCT) has been shown to be more effective at targeting tumors than the previous method of using only 10B for the treatment (Fig. IUPAC.64.2) [453] C. N. Culbertson, T. Jevremovic. Phys. Med. Biol.48, 3943 (2003).. 153Gd (with a half-life of 0.66 years) is used in the production of photon line sources (an optical source that emits one or more spectrally narrow lines as opposed to a continuous spectrum) to manufacture 153Gd line sources [454] V. M. Lebedev, J. N. Gordeev, E. A. Karelin, V. D. Gavrilov. Appl. Radiat. Isot.53, 829 (2000).. 153Gd is also used as a photon source of the dual-photon absorptiometry (DPA) technique that is used to measure bone mineral content (BMC). Studies for this technique have been conducted in horses and humans [455] A. Moure, P. Reichmann, H. R. Gamba. Phys. Med. Biol.48, 3851 (2003)., [456] P. Tothill, M. A. Smith, D. Sutton. Br. J. Radiol.56, 829 (1983)..
Gadolinium chemistry is mainly that of Gd³⁺ salts and oxides. Gadolinium(III) oxide, Gd₂O₃, is a stable refractory oxide and a common starting material. Gadolinium(III) chloride, GdCl₃, and gadolinium(III) nitrate, Gd(NO₃)₃, form hydrated salts and coordination complexes. Gadolinium(III) sulfate, Gd₂(SO₄)₃, and many organic chelates are also important. The +2 state is known in specialized solid-state and organometallic chemistry, but it is not the normal aqueous form.
See more information at the Gadolinium compound page.
Metallic gadolinium dust can burn and should be treated as a reactive metal powder. Soluble gadolinium salts are toxic at sufficient dose, largely because free Gd³⁺ can interfere with calcium-dependent biological processes. Medical contrast agents use tightly bound complexes, but release or retention of gadolinium is a recognized safety concern, especially in vulnerable patients. Stable gadolinium isotopes do not present a radiological hazard of practical importance.
Gadolinium occurs in nature dispersed with other rare-earth elements in minerals such as monazite and bastnäsite. It is not known to have an essential biological role. In soils and waters it tends to bind strongly to minerals, phosphates, carbonates, and organic matter rather than remain as a simple free ion. Anthropogenic gadolinium from contrast agents can pass through wastewater systems and has been detected as anomalous rare-earth patterns in some surface waters.
Gadolinium is not mined as a primary metal. It is recovered during processing of rare-earth ores, with separation from chemically similar lanthanides by solvent extraction or ion-exchange methods. Supply depends on the rare-earth industry as a whole and on the economics of separating mixed concentrates into individual oxides. Demand is smaller than for neodymium or cerium but important in medical imaging, nuclear technology, phosphors, and specialty magnetic materials. Recycling is limited and is most practical from concentrated industrial scrap rather than diffuse medical releases.
Gadolinium is found in several other minerals, including monazite and bastnasite, both of which are commercially important. With the development of ion-exchange and solvent extraction techniques, the availability and prices of gadolinium and the other rare-earth metals have greatly improved. The metal can be prepared by the reduction of the anhydrous fluoride with metallic calcium.
Gadolinium is a heavy element made mainly by neutron-capture processes in earlier generations of stars. Its stable isotopes include products associated with both slow and rapid neutron capture. In the Solar System it is far less abundant than iron or the light elements, but it follows the general rare-earth pattern in meteorites and planetary materials.
- Natural gadolinium has one of the highest thermal-neutron absorption capacities among stable-element mixtures.
- The element is named through gadolinite, a mineral ultimately named for Johan Gadolin.
- Gadolinium becomes ferromagnetic only just below ordinary room temperature.
- Free Gd³⁺ is far more hazardous than gadolinium held in approved chelating ligands.
- Gadolinium anomalies in rivers can trace releases from medical imaging agents.
画像
性質
物理的性質
- 原子半径（経験値）
- 180 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 196 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
- 237 pm 全元素のファンデルワールス半径を比較 →
- 密度
- 7900 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0199 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
- 1312.85 °C 全元素の融点を比較 →
- 沸点
- 3272.85 °C 全元素の沸点を比較 →
- 比熱容量
- 0.236 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 37.03 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 六方最密充填構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Pauling）
- 1.2 全元素の電気陰性度（Pauling）を比較 →
- 電子親和力
- 0.132 eV
- 第1イオン化エネルギー
- 6.1498 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
- 12.076042 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
- 20.540071 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
- 44.440153 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
- 64.800223 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- 0, +1, +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 5d1
熱力学的性質
- 融解熱
- 0.10364305 eV 全元素の融解熱を比較 →
- 蒸発熱
- 3.109292 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 4.124994 eV
- 原子化熱
- 4.124994 eV
- 原子化エンタルピー
- 4.119811 eV
原子核
- 陽子数
- 64 全元素の陽子数を比較 →
- 中性子数
- 94 全元素の中性子数を比較 →
- 既知の同位体
- 40 全元素の既知の同位体を比較 →
- 安定同位体
- 5 全元素の安定同位体を比較 →
- 最も安定な同位体
- Gd-158
- 発見年
- 1886
存在度
- 存在度（地殻）
- 6.2 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 7 × 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
- 364 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 25, 9, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-54-2 全元素のCAS登録番号を比較 →
- 項記号
- 9D°2
- InChI
- InChI=1S/Gd
- InChI Key
- UIWYJDYFSGRHKR-UHFFFAOYSA-N
電子配置 測定値
Gd: 4f⁷ 5d¹ 6s²[Xe] 4f⁷ 5d¹ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁷ 5d¹ 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
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 154 安定 | 153.9208741 ± 0.0000017 | 2.1800% | 安定 |
| 155 安定 | 154.9226305 ± 0.0000017 | 14.8000% | 安定 |
| 156 安定 | 155.9221312 ± 0.0000017 | 20.4700% | 安定 |
| 157 安定 | 156.9239686 ± 0.0000017 | 15.6500% | 安定 |
| 158 安定 | 157.9241123 ± 0.0000017 | 24.8400% | 安定 |
相／状態
理由: 融点（1312.85 °C）より1287.8 °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64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 |
|---|---|---|---|---|
| Gd I | 0 | 371 | 16 | 19 |
| Gd II | +1 | 465 | 0 | 17 |
| Gd III | +2 | 158 | 0 | 0 |
| Gd IV | +3 | 50 | 0 | 0 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Gd I | 0 | 634 |
| Gd II | +1 | 321 |
| Gd III | +2 | 28 |
| Gd IV | +3 | 5 |
| Gd V | +4 | 2 |
| Gd VI | +5 | 2 |
| Gd VII | +6 | 2 |
| Gd VIII | +7 | 2 |
| Gd IX | +8 | 2 |
| Gd X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +3 | 6 | データなし | 93.8 pm |
| +3 | 7 | データなし | 100 pm |
| +3 | 8 | データなし | 105.3 pm |
| +3 | 9 | データなし | 110.7 pm |
化合物
同位体 (5)
Natural gadolinium is a mixture of seven isotopes, but 17 isotopes of gadolinium are now recognized. Although two of these, 155Gd and 157Gd, have excellent capture characteristics, they are only present naturally in low concentrations. As a result, gadolinium has a very fast burnout rate and has limited use as a nuclear control rod material.
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 154 安定 | 153.9208741 ± 0.0000017 | 2.1800% ± 0.0300% | 安定 | stable | |
| 155 安定 | 154.9226305 ± 0.0000017 | 14.8000% ± 0.1200% | 安定 | stable | |
| 156 安定 | 155.9221312 ± 0.0000017 | 20.4700% ± 0.0900% | 安定 | stable | |
| 157 安定 | 156.9239686 ± 0.0000017 | 15.6500% ± 0.0200% | 安定 | stable | |
| 158 安定 | 157.9241123 ± 0.0000017 | 24.8400% ± 0.0700% | 安定 | stable |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 169 pm
- 共有結合半径（Pyykkö、二重結合）
- 135 pm
- 共有結合半径（Pyykkö、三重結合）
- 132 pm
ファンデルワールス半径
- Alvarez
- 283 pm
- UFF
- 336.8 pm
- MM3
- 271 pm
原子半径と金属半径
- 原子半径（Rahm）
- 277 pm
番号付けの尺度
- Mendeleev
- 27
- Pettifor
- 27
- Glawe
- 26
電気陰性度の尺度
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 7
- Robles–Bartolotti
- 6
分極率と分散
- 双極子分極率
- 158 a.u.
- 双極子分極率（不確かさ）
- 20 a.u.
- C₆ (Gould–Bučko)
- 2340 Ha·Bohr6
ミーデマパラメータ
- ミーデマモル体積
- 19.9 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 | 1586.15 K |
| 沸点 | 3546.15 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 | 1.2565 |
| 2 | p | 4.2946 |
| 2 | s | 16.783 |
| 3 | d | 13.723 |
| 3 | p | 19.8508 |
| 3 | s | 20.2903 |
| 4 | d | 34.3664 |
| 4 | f | 38.9864 |
| 4 | p | 31.3532 |
| 4 | s | 30.556 |
結晶半径の詳細 (4)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 3 | VI | 107.8 | from r^3 vs V plots, | |
| 3 | VII | 114 | ||
| 3 | VIII | 119.3 | from r^3 vs V plots, | |
| 3 | IX | 124.7 | from r^3 vs V plots, calculated, |
同位体の崩壊形式 (57)
| 同位体 | モード | 強度 |
|---|---|---|
| 133 | B+ | — |
| 133 | B+p | — |
| 134 | B+ | — |
| 134 | B+p | — |
| 135 | B+ | 100% |
| 135 | B+p | 2% |
| 136 | B+ | — |
| 136 | B+p | — |
| 137 | B+ | 100% |
| 137 | B+p | — |
X線散乱因子 (719)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 2.59886 |
| 10.1152 | — | 2.63957 |
| 10.2317 | — | 2.68119 |
| 10.3496 | — | 2.72415 |
| 10.4688 | — | 2.7678 |
| 10.5894 | — | 2.81214 |
| 10.7114 | — | 2.8572 |
| 10.8348 | — | 2.90298 |
| 10.9596 | — | 2.94949 |
| 11.0859 | — | 2.99675 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
6.2 milligrams per kilogram
参考文献 (1)
- [5] Gadolinium https://education.jlab.org/itselemental/ele064.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
7×10-7 milligrams per liter
参考文献 (1)
- [5] Gadolinium https://education.jlab.org/itselemental/ele064.html
Sources
Sources of this element.
Gadolinium is found in several other minerals, including monazite and bastnasite, both of which are commercially important. With the development of ion-exchange and solvent extraction techniques, the availability and prices of gadolinium and the other rare-earth metals have greatly improved. The metal can be prepared by the reduction of the anhydrous fluoride with metallic calcium.
参考文献 (1)
- [6] Gadolinium https://periodic.lanl.gov/64.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 Gadolinium.
The element property data was retrieved from publications.