Neodymium
[Xe] 4f⁴ 6s² · 2 · 8 · 18 · 22 · 8 · 2
The element of the strongest permanent magnets ever made. Neodymium-iron-boron is what let headphones, hard drives, electric motors and wind turbines become compact.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 60
- Atomic mass
- 144.242 а.е.м.
- Electron configuration
- [Xe] 4f⁴ 6s²
- Electrons per shell
- 2 · 8 · 18 · 22 · 8 · 2
- Block
- f-block
- Group
- no data
- Period
- 6
- Electronegativity (Pauling)
- 1.14
- Electronegativity (Allen)
- 1.09
- Atomic radius
- 229 pm
- Covalent radius
- 201 pm
- Van der Waals radius
- 229 pm
- Ionisation energy 1
- 533.1 kJ/mol
- Ionisation energy 2
- 1 040 kJ/mol
- Ionisation energy 3
- 2 130 kJ/mol
- Ionisation energy 4
- 3 900 kJ/mol
- Electron affinity
- 50 kJ/mol
- Common oxidation states
- +3
- Oxidation states
- +2, +3, +4
Physical properties
- State at 25 °C
- solid
- Density
- 7.01 g/cm³
- Melting point
- 1 297 K · 1 023.9 °C
- Boiling point
- 3 347 K · 3 073.9 °C
- Speed of sound
- 2 330 m/s
Thermal properties
- Heat of fusion
- 7.14 kJ/mol
- Heat of vaporisation
- 289 kJ/mol
- Specific heat capacity
- 0.19 J/(g·K)
- Thermal conductivity
- 16.5 W/(m·K)
Mechanical properties
- Young's modulus
- 41.4 GPa
- Shear modulus
- 16.3 GPa
- Bulk modulus
- 31.8 GPa
- Poisson ratio
- 0.28
- Mohs hardness
- no data
- Brinell hardness
- 265 MPa
Electrical and magnetic properties
- Electrical resistivity
- 643 nΩ·m
- Magnetic ordering
- antiferromagnetic
- Curie point
- no data
- Néel point
- 19 K
- Superconducting point
- no data
Crystal structure
- Crystal structure
- hexagonal close-packed (hcp)
- Lattice constants
- a = 365.8 pm · c = 1 179.7 pm
Abundance
- In the crust
- 41.5 mg/kg
- In the ocean
- 2.8·10⁻⁶ mg/L
- In the universe
- 1 mg/kg
- In the human body
- 0 mg/kg
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 142Nd | 27.152 % | stable | — |
| 143Nd | 12.174 % | stable | — |
| 144Nd | 23.798 % | 2.282·10⁶ Gyr | α |
| 145Nd | 8.293 % | stable | — |
| 146Nd | 17.189 % | stable | — |
| 148Nd | 5.756 % | stable | — |
| 150Nd | 5.638 % | stable | — |
Samarium-neodymium dating, from the decay of samarium-147, is applied to Earth's oldest rocks and to lunar samples.
Discovery
- Year of discovery
- 1885
- Discovered by
- Carl Auer von Welsbach
- Where
- Austria
- Origin of the name
- from Greek neos didymos (new twin)
History
Auer von Welsbach split Mosander's didymium into two elements in 1885 and called one of them the new twin. Nd-Fe-B magnets arrived almost a century later, in 1984.
Where it occurs
41.5 mg/kg of the crust — commoner than cobalt. The main sources are bastnäsite and monazite.
How it is produced
By solvent-extraction separation of rare-earth concentrates, then electrolysis of molten fluorides. Over 80 % of world output is in China.
Role in living things
No biological role.
Safety
Of low toxicity, but strong neodymium magnets are mechanically dangerous: they pinch fingers, and magnets swallowed by children attract through bowel walls and cause perforation.
Uses
- Nd-Fe-B magnets: motors, wind turbine generators, loudspeakers, hard drive actuators
- Nd:YAG lasers — the workhorse of industrial cutting and of medicine
- Glass for welding goggles and art glass that changes colour with the light
- Ceramic capacitors
Curiosities
- A modern wind turbine can hold up to 600 kg of neodymium magnets.
- Neodymium glass shifts from lilac to blue depending on the light source — a rare alexandrite-like colour change.
- Nd-Fe-B magnets are thirty times stronger than ferrite ones of the same size.
- The inventors of neodymium magnets worked in Japan and the United States simultaneously and presented at the same 1984 conference.