Neodymium (Nd)
lanthanideSolid
Masse atomique relative standard
144,242 uConfiguration électronique
[Xe] 6s2 4f4Point de fusion
1020,85 °CPoint d’ébullition
3073,85 °CMasse volumique
7010 kg/m³États d’oxydation
0, +2, +3, +4Électronégativité (Pauling)
1,14Énergie d’ionisation (1re)
5,52475 eVAnnée de découverte
1841Rayon atomique
185 pmDétails
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.
Images
Propriétés
Propriétés physiques
- Rayon atomique (empirique)
- 185 pm Comparer : Rayon atomique (empirique) de tous les éléments →
- Rayon covalent
- 201 pm Comparer : Rayon covalent de tous les éléments →
- Rayon de van der Waals
- 229 pm Comparer : Rayon de van der Waals de tous les éléments →
- Masse volumique
- 7010 kg/m³ Comparer : Masse volumique de tous les éléments →
- Volume molaire
- 0,0206 L/mol
- Phase aux CNTP
- Solide Comparer : Phase aux CNTP de tous les éléments →
- Point de fusion
- 1020,85 °C Comparer : Point de fusion de tous les éléments →
- Point d’ébullition
- 3073,85 °C Comparer : Point d’ébullition de tous les éléments →
- Capacité thermique massique
- 0,19 J/(g·K) Comparer : Capacité thermique massique de tous les éléments →
- Capacité thermique molaire
- 27,45 J/(mol·K) Comparer : Capacité thermique molaire de tous les éléments →
- Structure cristalline
- Hexagonal compact Comparer : Structure cristalline de tous les éléments →
Propriétés chimiques
- Électronégativité (Pauling)
- 1,14 Comparer : Électronégativité (Pauling) de tous les éléments →
- Affinité électronique
- 1,913 eV
- Énergie d’ionisation (1re)
- 5,52475 eV Comparer : Énergie d’ionisation (1re) de tous les éléments →
- Énergie d’ionisation (2e)
- 10,783037 eV Comparer : Énergie d’ionisation (2e) de tous les éléments →
- Énergie d’ionisation (3e)
- 22,090076 eV Comparer : Énergie d’ionisation (3e) de tous les éléments →
- Énergie d’ionisation (4e)
- 40,60014 eV Comparer : Énergie d’ionisation (4e) de tous les éléments →
- Énergie d’ionisation (5e)
- 60,000207 eV Comparer : Énergie d’ionisation (5e) de tous les éléments →
- États d’oxydation
- 0, +2, +3, +4 Comparer : États d’oxydation de tous les éléments →
- Électrons de valence
- 3 Comparer : Électrons de valence de tous les éléments →
- Configuration électronique
- [Xe] 6s2 4f4
Propriétés thermodynamiques
- Enthalpie de fusion
- 0,07400114 eV Comparer : Enthalpie de fusion de tous les éléments →
- Enthalpie de vaporisation
- 2,829455 eV Comparer : Enthalpie de vaporisation de tous les éléments →
- Enthalpie de sublimation
- 2,995284 eV
- Enthalpie d’atomisation
- 2,995284 eV
- Enthalpie d’atomisation
- 3,388091 eV
Propriétés nucléaires
- Protons
- 60 Comparer : Protons de tous les éléments →
- Neutrons
- 82 Comparer : Neutrons de tous les éléments →
- Isotopes connus
- 40 Comparer : Isotopes connus de tous les éléments →
- Isotopes stables
- 1 Comparer : Isotopes stables de tous les éléments →
- Isotope le plus stable
- Nd-142
- Année de découverte
- 1841
Abondance
- Abondance (croûte terrestre)
- 41,5 mg/kg Comparer : Abondance (croûte terrestre) de tous les éléments →
- Abondance (océan)
- 2,8 × 10−6 mg/L Comparer : Abondance (océan) de tous les éléments →
Structure cristalline
- Paramètre de maille a
- 366 pm
Structure électronique
- Électrons par couche
- 2, 8, 18, 22, 8, 2 Comparer : Électrons par couche de tous les éléments →
Identifiants
- Numéro CAS
- 7440-00-8 Comparer : Numéro CAS de tous les éléments →
- Symbole de terme
- 5I4
- InChI
- InChI=1S/Nd
- Clé InChI
- QEFYFXOXNSNQGX-UHFFFAOYSA-N
Configuration électronique Mesuré
Nd: 4f⁴ 6s²[Xe] 4f⁴ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁴ 6s²Modèle atomique
Les isotopes diffèrent par leur nombre de neutrons, leur masse et leur stabilité — pas par la configuration électronique de l’atome neutre.
Modèle atomique schématique, non à l’échelle.
Empreinte atomique
Spectre d’émission / d’absorption
Distribution isotopique
| Nombre de masse | Masse atomique (u) | Abondance naturelle | Demi-vie |
|---|---|---|---|
| 142 Stable | 141,907729 ± 0,000002 | 27,1520% | Stable |
Phase / État
Explication: 995,9 °C en dessous du point de fusion (1020,85 °C)
Schématique, non à l’échelle
Points de transition de phase
Énergies de transition
Énergie nécessaire pour faire fondre 1 mol au point de fusion
Énergie nécessaire pour vaporiser 1 mol au point d’ébullition
Énergie nécessaire pour sublimer 1 mol au point de sublimation
Masse volumique
Dans les conditions standard
Dans les conditions standard
Spectres atomiques
Affichage de 10 sur 60. Tri par charge ionique croissante.
Raies répertoriées ?
| Ion | Charge | Nombre total de raies | Probabilités de transition | Désignations des niveaux |
|---|---|---|---|---|
| Nd I | 0 | 118 | 9 | 9 |
| Nd II | +1 | 617 | 255 | 600 |
Niveaux répertoriés ?
| Ion | Charge | Niveaux |
|---|---|---|
| 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 |
Rayons ioniques
| Charge | Coordinence | Spin | Rayon |
|---|---|---|---|
| +2 | 8 | N/D | 129 pm |
| +2 | 9 | N/D | 135 pm |
| +3 | 6 | N/D | 98.3 pm |
| +3 | 8 | N/D | 110.9 pm |
| +3 | 9 | N/D | 116.3 pm |
| +3 | 12 | N/D | 127 pm |
Composés
Isotopes (1)
Natural neodymium is a mixture of seven stable isotopes. Fourteen other radioactive isotopes are recognized.
| Nombre de masse | Masse atomique (u) | Abondance naturelle | Demi-vie | Mode de désintégration | |
|---|---|---|---|---|---|
| 142 Stable | 141,907729 ± 0,000002 | 27,1520% ± 0,0400% | Stable | stable |
Propriétés étendues
Rayons covalents (données étendues)
- Rayon covalent (Pyykkö)
- 174 pm
- Rayon covalent (Pyykkö, liaison double)
- 137 pm
Rayons de van der Waals
- Alvarez
- 295 pm
- UFF
- 357,5 pm
- MM3
- 273 pm
Rayons atomiques et métalliques
- Rayon atomique (Rahm)
- 284 pm
Échelles de numérotation
- Mendeleev
- 19
- Pettifor
- 30
- Glawe
- 29
Échelles d’électronégativité
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarisabilité et dispersion
- Polarisabilité dipolaire
- 208 a.u.
- Polarisabilité dipolaire (incertitude)
- 20 a.u.
- C₆ (Gould–Bučko)
- 3560 Ha·Bohr6
Paramètres de Miedema
- Volume molaire de Miedema
- 20,58 cm3/mol
- Densité électronique de Miedema
- 2
Risque d’approvisionnement et économie
- Concentration de la production
- 97
- Risque relatif d’approvisionnement
- 10
- Répartition des réserves
- 50
- Stabilité politique (principal producteur)
- 24
- Stabilité politique (principal détenteur de réserves)
- 24
Transitions de phase et allotropes
| Point de fusion | 1289,15 K |
| Point d’ébullition | 3347,15 K |
Catégories d’états d’oxydation
Données de référence avancées
Constantes d’écran (13)
| n | Orbitale | 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 |
Détail des rayons cristallins (6)
| Charge | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 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, |
Modes de désintégration des isotopes (52)
| Isotope | Mode | Intensité |
|---|---|---|
| 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% |
Facteurs de diffusion des rayons X (508)
| Énergie (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 |
Données complémentaires
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
4.15×101 milligrams per kilogram
Références (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
Références (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.
Références (1)
- [6] Neodymium https://periodic.lanl.gov/60.shtml
Références
(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.