Neodymium (Nd)
lanthanideSolid
Standard Atomic Weight
144.242 uElectron configuration
[Xe] 6s2 4f4Melting point
1020.85 °CBoiling point
3073.85 °CDensity
7010 kg/m³Oxidation states
0, +2, +3, +4Electronegativity (Pauling)
1.14Ionization energy (1st)
5.52475 eVDiscovery year
1841Atomic radius
185 pmDetails
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
Properties
Physical
- Atomic radius (empirical)
- 185 pm Compare Atomic radius (empirical) of all elements →
- Covalent radius
- 201 pm Compare Covalent radius of all elements →
- Van der Waals radius
- 229 pm Compare Van der Waals radius of all elements →
- Density
- 7010 kg/m³ Compare Density of all elements →
- Molar volume
- 0.0206 L/mol
- Phase at STP
- Solid Compare Phase at STP of all elements →
- Melting point
- 1020.85 °C Compare Melting point of all elements →
- Boiling point
- 3073.85 °C Compare Boiling point of all elements →
- Specific heat capacity
- 0.19 J/(g·K) Compare Specific heat capacity of all elements →
- Molar heat capacity
- 27.45 J/(mol·K) Compare Molar heat capacity of all elements →
- Crystal structure
- Hexagonal close-packed Compare Crystal structure of all elements →
Chemical
- Electronegativity (Pauling)
- 1.14 Compare Electronegativity (Pauling) of all elements →
- Electron affinity
- 1.913 eV
- Ionization energy (1st)
- 5.52475 eV Compare Ionization energy (1st) of all elements →
- Ionization energy (2nd)
- 10.783037 eV Compare Ionization energy (2nd) of all elements →
- Ionization energy (3rd)
- 22.090076 eV Compare Ionization energy (3rd) of all elements →
- Ionization energy (4th)
- 40.60014 eV Compare Ionization energy (4th) of all elements →
- Ionization energy (5th)
- 60.000207 eV Compare Ionization energy (5th) of all elements →
- Oxidation states
- 0, +2, +3, +4 Compare Oxidation states of all elements →
- Valence electrons
- 3 Compare Valence electrons of all elements →
- Electron configuration
- [Xe] 6s2 4f4
Thermodynamic
- Heat of fusion
- 0.07400114 eV Compare Heat of fusion of all elements →
- Heat of vaporization
- 2.829455 eV Compare Heat of vaporization of all elements →
- Heat of sublimation
- 2.995284 eV
- Heat of atomization
- 2.995284 eV
- Atomization enthalpy
- 3.388091 eV
Nuclear
- Protons
- 60 Compare Protons of all elements →
- Neutrons
- 82 Compare Neutrons of all elements →
- Known isotopes
- 40 Compare Known isotopes of all elements →
- Stable isotopes
- 1 Compare Stable isotopes of all elements →
- Most stable isotope
- Nd-142
- Discovery year
- 1841
Abundance
- Abundance (Earth's crust)
- 41.5 mg/kg Compare Abundance (Earth's crust) of all elements →
- Abundance (ocean)
- 2.8 × 10−6 mg/L Compare Abundance (ocean) of all elements →
Crystal Structure
- Lattice constant a
- 366 pm
Electronic Structure
- Electrons per shell
- 2, 8, 18, 22, 8, 2 Compare Electrons per shell of all elements →
Identifiers
- CAS number
- 7440-00-8 Compare CAS number of all elements →
- Term symbol
- 5I4
- InChI
- InChI=1S/Nd
- InChI Key
- QEFYFXOXNSNQGX-UHFFFAOYSA-N
Electron Configuration Measured
Nd: 4f⁴ 6s²[Xe] 4f⁴ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁴ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 142 Stable | 141.907729 ± 0.000002 | 27.1520% | Stable |
Phase / State
Reason: 995.9 °C below melting point (1020.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 60. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Nd I | 0 | 118 | 9 | 9 |
| Nd II | +1 | 617 | 255 | 600 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| 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 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +2 | 8 | N/A | 129 pm |
| +2 | 9 | N/A | 135 pm |
| +3 | 6 | N/A | 98.3 pm |
| +3 | 8 | N/A | 110.9 pm |
| +3 | 9 | N/A | 116.3 pm |
| +3 | 12 | N/A | 127 pm |
Compounds
Isotopes (1)
Natural neodymium is a mixture of seven stable isotopes. Fourteen other radioactive isotopes are recognized.
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 142 Stable | 141.907729 ± 0.000002 | 27.1520% ± 0.0400% | Stable | stable |
Extended Properties
Covalent Radii (Extended)
- Covalent radius (Pyykkö)
- 174 pm
- Covalent radius (Pyykkö, double)
- 137 pm
Van der Waals Radii
- Alvarez
- 295 pm
- UFF
- 357.5 pm
- MM3
- 273 pm
Atomic & Metallic Radii
- Atomic radius (Rahm)
- 284 pm
Numbering Scales
- Mendeleev
- 19
- Pettifor
- 30
- Glawe
- 29
Electronegativity Scales
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarizability & Dispersion
- Dipole polarizability
- 208 a.u.
- Dipole polarizability (unc.)
- 20 a.u.
- C₆ (Gould–Bučko)
- 3560 Ha·Bohr6
Miedema Parameters
- Miedema molar volume
- 20.58 cm3/mol
- Miedema electron density
- 2
Supply Risk & Economics
- Production concentration
- 97
- Relative supply risk
- 10
- Reserve distribution
- 50
- Political stability (top producer)
- 24
- Political stability (top reserve)
- 24
Phase Transitions & Allotropes
| Melting point | 1289.15 K |
| Boiling point | 3347.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (13)
| n | Orbital | 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 |
Crystal Radii Detail (6)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 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, |
Isotope Decay Modes (52)
| Isotope | Mode | Intensity |
|---|---|---|
| 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‑ray Scattering Factors (508)
| Energy (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 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
4.15×101 milligrams per kilogram
References (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
References (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.
References (1)
- [6] Neodymium https://periodic.lanl.gov/60.shtml
References
(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.
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This section provides all form of data related to element Neodymium.
The element property data was retrieved from publications.