Neodymium (Nd)
lanthanideSolid
標準原子量
144.242 u電子配置
[Xe] 6s2 4f4融点
1020.85 °C沸点
3073.85 °C密度
7010 kg/m³酸化数
0, +2, +3, +4電気陰性度（Pauling）
1.14第1イオン化エネルギー
5.52475 eV発見年
1841原子半径
185 pm詳細
Neodymium is a light lanthanide metal and one of the more abundant rare-earth elements. It occurs in minerals with other lanthanides rather than as a native element. Its chemistry is dominated by the trivalent ion Nd³⁺, which gives many salts and glasses a pink to violet color. Technologically, neodymium is most important in high-strength permanent magnets and in optically active glasses and crystals.
The metal has a bright silvery metallic luster, Neodymium is one of the more reactive rare-earth metals and quickly tarnishes in air, forming an oxide that spalls off and exposes metal to oxidation. The metal, therefore, should be kept under light mineral oil or sealed in a plastic material. Neodymium exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at 863°C.
The name derives from the Greek neos for "new" and didymos for "twin". It was discovered by the Swedish surgeon and chemist Carl Gustav Mosander in 1841, who called it didymium (or twin) because of its similarity to lanthanum, which he had previously discovered two years earlier. In 1885, the Austrian chemist Carl Auer (Baron von Welsbach) separated didymium into two elements, one of which he called neodymium (or new twin).
Neodymium was discovered by Carl F. Auer von Welsbach, an Austrian chemist, in 1885. He separated neodymium, as well as the element praseodymium, from a material known as didymium. Today, neodymium is primarily obtained from through an ion exchange process monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements.
From the Greek word neos meaning new, and didymos, twin. In 1841, Mosander, extracted a rose-colored oxide from cerite , which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals.
Pure neodymium is a bright, silvery metal when freshly cut, but it tarnishes in air as an oxide layer forms. It is relatively soft and can be cut with a knife. The metal slowly reacts with moisture and oxidizes more rapidly when finely divided or heated.
The largest use of neodymium is in neodymium-iron-boron permanent magnets, commonly based on the Nd₂Fe₁₄B phase. These magnets are used in electric motors, generators, hard-disk drives, loudspeakers, sensors, and magnetic couplings. Neodymium-doped yttrium aluminium garnet, Nd:Y₃Al₅O₁₂, is a major solid-state laser material. Neodymium compounds are also used to color and filter glass, including didymium-type eyewear for glassworking.
Neodymium makes up about 18% of Misch metal, a material that is used to make flints for lighters. Neodymium is also a component of didymium glass, which is used to make certain types of welder's and glass blower's goggles. Neodymium is added to glass to remove the green color caused by iron contaminants. It can also be added to glass to create violet, red or gray colors. Some types of glass containing neodymium are used by astronomers to calibrate devices called spectrometers and other types are used to create artificial rubies for lasers. Some neodymium salts are used to color enamels and glazes.
Didymium, of which neodymium is a component, is used for coloring glass to make welders goggles. By itself, neodymium colors glass delicate shades ranging from pure violet through wine-red and warm gray. Light transmitted through such glass shows unusually sharp absorption bands. The glass has been used in astronomical work to produce sharp bands by which spectral lines may be calibrated. Glass containing neodymium can be used as a laser material to produce coherent light. Neodymium salts are also used as a colorant for enamels.
Isotopes in Geochronology
143Nd is a radiogenic isotope produced by decay of 147Sm, with a half-life of 1.06×1011 years. Thus, the isotope-amount ratio n(143Nd)/n(144Nd) can be used for dating rocks on long time scales and as a chemical tracer in geochemistry (Fig. IUPAC.60.1) [427] M. T. McCullocha, M. R. Perfita. Earth. Planet. Sci. Lett.56, 167 (1981)., [428] R. Eichhorn, R. Höll, E. Jagoutz, U. Schärer. Geochim. Cosmochim. Acta61, 5005 (1997).. The very small accumulation of 142Nd in billion-year-old metamorphosed rocks from Greenland [from the relatively short-lived (about 68×106 years) alpha decay of 146Sm] provided evidence that the crust of the Earth formed before the young planet was more than 100×106 years old. This is because only a short amount of time could have elapse to incorporate the 146Sm parent radionuclide into the ancient Greenland minerals before it decayed [429] M. G. Jackson, S. R. Hart, A. A. P. Koppers, H. Staudigel, J. Konter, J. Blusztajn, M. Kurz, J. A. Russell. Nature448, 684 (2007)., [430] G. Caro, B. Bourdon, J. L. Birck, S. Moorbath. Nature423, 428 (2003)..
Isotopes Used as a Source of Radioactive Isotope(s)
146Nd has been used in the production of 147Pm (with a half-life of 2.6 years), via the reaction 146Nd (n, γ) 147Nd, which is followed by a subsequent electron decay reaction, 147Nd→ 147Pm+β - reaction. 147Pm is a radioactive power-generation source [431] C. S. Lee, Y. M. Wang, W. L. Cheng, G. Ting. J. Radioanal. Nucl. Chem.130, 21 (1988)..
Neodymium most commonly forms compounds in the +3 oxidation state, and Nd³⁺ salts are typically pale pink, rose, lavender, or violet depending on ligand and hydration. Important compounds include neodymium(III) oxide, Nd₂O₃, neodymium(III) chloride, NdCl₃, and neodymium(III) fluoride, NdF₃. The oxide is a common intermediate in separation and materials production. Divalent neodymium is known in some solid-state compounds, but it is much less stable and far less common than Nd³⁺ chemistry.
See more information at the Neodymium compound page.
Bulk neodymium metal has low acute toxicity but is reactive as a fine powder and can present a fire hazard. Dusts and soluble salts should be handled as industrial chemical hazards because rare-earth compounds can irritate the eyes, skin, and respiratory tract. Strong neodymium magnets create mechanical hazards: they can pinch skin, shatter on impact, damage magnetic media, and interfere with some implanted medical devices.
Neodymium has a low-to-moderate acute toxic rating. As with other rare earths, neodymium should be handled with care.
Neodymium is widely dispersed in the crust, mainly in rare-earth minerals such as monazite and bastnäsite. In natural waters it is present at very low concentrations and tends to bind to particles, phosphates, carbonates, and organic matter rather than remain as a free ion. Mining and processing can disturb soils and generate waste streams containing other rare earths, thorium, uranium, acids, or salts, depending on the ore and process.
Neodymium is produced by mining rare-earth ores, separating mixed lanthanides through solvent extraction or ion-exchange processes, and reducing suitable halides or oxides to metal when needed. Demand is strongly tied to Nd-Fe-B magnets, often with praseodymium partly substituting for neodymium and dysprosium or terbium added for high-temperature performance. Supply is constrained by the difficulty of separating similar lanthanides and by the environmental controls needed for ore processing. Recycling from magnets is technically possible and increasing, but collection and separation remain limiting factors.
Made from electrolysis of its halide salts, which are made from monazite sand.
Neodymium is produced mainly by neutron-capture nucleosynthesis in evolved stars and stellar explosions, with contributions from both slow and rapid neutron-capture processes. It is less abundant than lighter elements but is a normal trace constituent of the Solar System. Meteorites and planetary rocks contain neodymium in rare-earth patterns useful for geochemical and isotopic studies.
- The name neodymium means “new twin,” reflecting its separation from didymium.
- Natural neodymium consists of several stable isotopes and very long-lived radioactive ¹⁴⁴Nd and ¹⁵⁰Nd.
- Neodymium glass can appear different colors under different lighting because of sharp f-electron absorption bands.
- Nd-Fe-B magnets are usually coated because the alloy corrodes readily.
- Samarium-cobalt magnets tolerate heat better, but Nd-Fe-B magnets usually provide stronger fields for their size.
画像
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
- 201 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
- 229 pm 全元素のファンデルワールス半径を比較 →
- 密度
- 7010 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0206 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
- 1020.85 °C 全元素の融点を比較 →
- 沸点
- 3073.85 °C 全元素の沸点を比較 →
- 比熱容量
- 0.19 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 27.45 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）
- 1.14 全元素の電気陰性度（Pauling）を比較 →
- 電子親和力
- 1.913 eV
- 第1イオン化エネルギー
- 5.52475 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
- 10.783037 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
- 22.090076 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
- 40.60014 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
- 60.000207 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, +4 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 4f4
熱力学的性質
- 融解熱
- 0.07400114 eV 全元素の融解熱を比較 →
- 蒸発熱
- 2.829455 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 2.995284 eV
- 原子化熱
- 2.995284 eV
- 原子化エンタルピー
- 3.388091 eV
原子核
- 陽子数
- 60 全元素の陽子数を比較 →
- 中性子数
- 82 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
- 1 全元素の安定同位体を比較 →
- 最も安定な同位体
- Nd-142
- 発見年
- 1841
存在度
- 存在度（地殻）
- 41.5 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 2.8 × 10−6 mg/L 全元素の存在度（海洋）を比較 →
結晶構造
- 格子定数a
- 366 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 22, 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
- 7440-00-8 全元素のCAS登録番号を比較 →
- 項記号
- 5I4
- InChI
- InChI=1S/Nd
- InChI Key
- QEFYFXOXNSNQGX-UHFFFAOYSA-N
電子配置 測定値
Nd: 4f⁴ 6s²[Xe] 4f⁴ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁴ 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 |
|---|---|---|---|
| 142 安定 | 141.907729 ± 0.000002 | 27.1520% | 安定 |
相／状態
理由: 融点（1020.85 °C）より995.9 °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60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。
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Nd I | 0 | 739 |
| Nd II | +1 | 840 |
| Nd III | +2 | 31 |
| Nd IV | +3 | 19 |
| Nd V | +4 | 2 |
| Nd VI | +5 | 2 |
| Nd VII | +6 | 2 |
| Nd VIII | +7 | 2 |
| Nd IX | +8 | 2 |
| Nd X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +2 | 8 | データなし | 129 pm |
| +2 | 9 | データなし | 135 pm |
| +3 | 6 | データなし | 98.3 pm |
| +3 | 8 | データなし | 110.9 pm |
| +3 | 9 | データなし | 116.3 pm |
| +3 | 12 | データなし | 127 pm |
化合物
同位体 (1)
Natural neodymium is a mixture of seven stable isotopes. Fourteen other radioactive isotopes are recognized.
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 142 安定 | 141.907729 ± 0.000002 | 27.1520% ± 0.0400% | 安定 | stable |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 174 pm
- 共有結合半径（Pyykkö、二重結合）
- 137 pm
ファンデルワールス半径
- Alvarez
- 295 pm
- UFF
- 357.5 pm
- MM3
- 273 pm
原子半径と金属半径
- 原子半径（Rahm）
- 284 pm
番号付けの尺度
- Mendeleev
- 19
- Pettifor
- 30
- Glawe
- 29
電気陰性度の尺度
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
分極率と分散
- 双極子分極率
- 208 a.u.
- 双極子分極率（不確かさ）
- 20 a.u.
- C₆ (Gould–Bučko)
- 3560 Ha·Bohr6
ミーデマパラメータ
- ミーデマモル体積
- 20.58 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 | 1289.15 K |
| 沸点 | 3347.15 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 | 1.1868 |
| 2 | p | 4.2434 |
| 2 | s | 15.7838 |
| 3 | d | 13.8432 |
| 3 | p | 19.311 |
| 3 | s | 19.6572 |
| 4 | d | 33.1908 |
| 4 | f | 37.734 |
| 4 | p | 29.986 |
| 4 | s | 29.0136 |
結晶半径の詳細 (6)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 2 | VIII | 143 | ||
| 2 | IX | 149 | ||
| 3 | VI | 112.3 | from r^3 vs V plots, | |
| 3 | VIII | 124.9 | from r^3 vs V plots, | |
| 3 | IX | 130.3 | from r^3 vs V plots, | |
| 3 | XII | 141 | estimated, |
同位体の崩壊形式 (52)
| 同位体 | モード | 強度 |
|---|---|---|
| 124 | B+ | — |
| 124 | B+p | — |
| 125 | B+ | 100% |
| 125 | B+p | 0% |
| 126 | B+ | — |
| 126 | B+p | — |
| 127 | B+ | 100% |
| 127 | B+p | — |
| 128 | B+ | — |
| 129 | B+ | 100% |
X線散乱因子 (508)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.24448 |
| 10.1617 | — | 0.25177 |
| 10.3261 | — | 0.25926 |
| 10.4931 | — | 0.26698 |
| 10.6628 | — | 0.27494 |
| 10.8353 | — | 0.28312 |
| 11.0106 | — | 0.29156 |
| 11.1886 | — | 0.30024 |
| 11.3696 | — | 0.30918 |
| 11.5535 | — | 0.31839 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
4.15×101 milligrams per kilogram
参考文献 (1)
- [5] Neodymium https://education.jlab.org/itselemental/ele060.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
2.8×10-6 milligrams per liter
参考文献 (1)
- [5] Neodymium https://education.jlab.org/itselemental/ele060.html
Production
Production of this element (from raw materials or other compounds containing the element).
The element may be obtained by separating neodymium salts from other rare earths by ion-exchange or solvent extraction techniques, and by reducing anhydrous halides such as NdF3 with calcium metal. Other separation techniques are possible.
参考文献 (1)
- [6] Neodymium https://periodic.lanl.gov/60.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 Neodymium.
The element property data was retrieved from publications.