Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime.
Identity
- Atomic mass
- 162.5 u
- Category
- Lanthanides
- Group
- 3
- Period
- 6
- Block
- f
- Oxidation States
- +3
- Phase (25 °C)
- Solid
- Appearance
- silvery white
Electronic Structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f10
- Short configuration
- [Xe] 4f10 6s2
- Electrons per shell
- 2, 8, 18, 28, 8, 2
- Electronegativity (Pauling)
- 1.22
- Electron affinity
- 34.0 kJ/mol
- 1st ionization energy
- 573 kJ/mol
- Ionization energies
- 573 · 1130 · 2200 · 3990 kJ/mol
Physical properties
- Melting point
- 1406.8 °C (1680 K)
- Boiling point
- 2566.8 °C (2840 K)
- Density
- 8.54 g/cm³
- Molar heat capacity
- 27.7 J/(mol·K)
Chemical behavior of dysprosium
Dysprosium has ten outer electrons ([Xe] 4f¹⁰ 6s²) and almost always acts as +3, with low electronegativity (1.22). It forms highly ionic bonds and is very magnetic: added to neodymium it raises coercivity at high temperatures. It is soft, oxidizes slowly in dry air and rapidly in moist air, and absorbs neutrons with great efficiency.
Reactivity
4 Dy + 3 O₂ → 2 Dy₂O₃
In dry air it tarnishes slowly; in moist air it becomes covered with a greenish oxide that flakes off. When heated, it burns to the oxide.
2 Dy + 6 H₂O → 2 Dy(OH)₃ + 3 H₂
It reacts with water releasing hydrogen, faster when hot. Magnets containing dysprosium resist better because the Nd-Fe-B matrix protects it.
2 Dy + 6 HCl → 2 DyCl₃ + 3 H₂
It dissolves in acids giving yellowish dysprosium(III) salts. The chloride feeds the diffusion into the grain boundaries of the magnets.
2 Dy + 3 I₂ → 2 DyI₃
With iodine it gives the iodide, which in metal halide lamps produces extremely intense white light when it vaporizes in the arc.
Notable compounds
| Compound | Formula | Use or importance |
|---|---|---|
| Dysprosium oxide | Dy₂O₃ | Thermal magnets and nuclear ceramics |
| Dysprosium iodide | DyI₃ | Intense white-light lamps |
| Nd-Dy-Fe-B magnet | NdDyFeB | Electric motors and wind power |
| Dysprosium chloride | DyCl₃ | Diffusion in magnets and catalysts |
| Dysprosium boride | DyB₆ | Cathodes and magnetic materials |
Electron shell distribution
View in the atom builderIsotopes
Natural dysprosium mixes seven stable isotopes: 156Dy (~0.06%), 158Dy (~0.10%), 160Dy (~2.3%), 161Dy (~18.9%), 162Dy (~25.5%), 163Dy (~24.9%) and 164Dy (~28.3%), all with 66 protons. 164Dy has the greatest neutron capture cross section among the stable ones and is used in control rods.
Occurrence and production
It appears at about 5 ppm, in bastnasite, monazite and above all xenotime and the ionic clays of southern China, rich in heavy elements. Its production is highly concentrated geographically. It is obtained by acid dissolution, solvent extraction and fine chromatographic separation.
History and origin of the name
Paul-Émile Lecoq de Boisbaudran discovered it in 1886 in impure holmia and named it dysprosium, from the Greek dysprositos (hard to obtain): a prophetic name. Its pure separation was achieved by Urbain in the 20th century. For a century it was a rarity until electric cars made it critical.
Applications and relevance of dysprosium
Uses of the element
As an additive to neodymium (1–8%) it keeps the magnetism up to 200 °C in motors and wind turbines. It also enters Terfenol-D for sonars and magnetocaloric alloys for refrigeration without gases.
Uses of its compounds
The iodide lights stadiums and cinemas with near-daylight white light; the oxide absorbs neutrons in control rods and dopes ceramics. Dysprosium lasers emit in the mid-infrared for gas sensors.
Health, safety and environment
Biological role
It has no biological function and its toxicity is low in the usual forms. Finished magnets do not release dysprosium; the exposure is occupational, from machining dust.
Safety
Fine powder can be pyrophoric and ignite in air, so it is machined with coolant and extraction. Powerful magnets carry a mechanical risk from trapping and from ingesting small pieces.
Environment
It is the most critical lanthanide: concentrated supply, growing demand and still-low recycling. Reducing its dose through grain-boundary diffusion and recycling wind turbine and vehicle magnets are the ways to ease its mining footprint.
Frequently asked questions about Dysprosium
Why is dysprosium important in neodymium magnets?
Dysprosium is added to neodymium–iron–boron magnets to increase their resistance to demagnetization when they work at high temperatures. This is essential in vehicle electric motors, wind generators and industrial equipment, where heat can reduce magnetic performance. By improving coercivity, dysprosium allows the magnet to keep its field even in demanding conditions, although it also makes the material more expensive because of its high strategic demand.
Is dysprosium dangerous?
Dysprosium has low toxicity and no essential biological function is known in the body. However, the pure metal reacts with air and water, and fine powder can be pyrophoric, that is, capable of igniting easily. For this reason, its industrial handling requires atmosphere control, fire protection and measures to avoid inhalation. Finished magnets and components do not represent a habitual exposure for the user.
Why is dysprosium considered a critical material?
It is considered critical because it is difficult to substitute in high-performance magnets that must operate with heat, and because its supply chain is highly concentrated in few countries. Electric vehicle motors and wind generators depend on magnets that are stable at elevated temperature, and dysprosium is one of the most effective additives to achieve it. This combination of technological importance, limited supply and difficulty of recycling raises its strategic value.
Can a neodymium magnet be made without dysprosium?
Yes, but it can lose performance at high temperatures. There are techniques to reduce the amount of dysprosium, such as diffusing dysprosium into the grain boundaries of the magnet or redesigning the motor and the cooling system. These strategies seek to keep heat resistance while using less material. Even so, in very demanding applications such as electric motors and wind turbines, dysprosium remains hard to replace completely.
What is dysprosium used for in nuclear reactors?
Dysprosium absorbs neutrons with great efficiency, a property taken advantage of in control rods and neutron-absorbing materials of nuclear reactors. By capturing neutrons, it helps regulate the chain reaction and keep operation within safe limits. In addition, certain dysprosium compounds keep their structural stability after prolonged irradiation, something valuable in components exposed to intense nuclear conditions.
Where does dysprosium come from?
Dysprosium is obtained mainly from rare-earth minerals such as bastnasite, monazite and xenotime, where it appears alongside other heavy lanthanides. After treatment of the ore, it is separated by solvent extraction and ion exchange. It is one of the elements considered strategic because its production is geographically concentrated and its demand grows with electric motors and wind turbines.
What other uses does dysprosium have besides magnets?
Besides improving magnets, dysprosium is used in materials for lasers, in metal halide discharge lamps —where its iodide contributes to an intense white light— and in nuclear reactor components. It is also being researched in molecular magnets and information storage technologies. Its magnetic, optical and neutron-absorbing properties explain this variety of specialized applications.
Main sources consulted: PubChem, Royal Society of Chemistry, NIST, IUPAC. Last revision: November 2026.