Dysprosium (Dy)

Metallic with a bright silvery-white lustre. Dysprosium belongs to the lanthanoids. It is relatively stable in air at room temperatures, it will however dissolve in mineral acids, evolving hydrogen. It is found in from rare-earth minerals. There are seven natural isotopes of dysprosium, and eight radioisotopes, Dy-154 being the most stable with a half-life of 3*10^6 years. Dysprosium is used as a neutron absorber in nuclear fission reactions, and in compact disks. It was discovered by Paul Emile Lecoq de Boisbaudran in 1886 in France. Its name comes from the Greek word dysprositos, which means hard to obtain.
Atomic Number66
Atomic Weight162.5
Mass Number164
Protons66 p+
Neutrons98 n0
Electrons66 e-
Dysprosium1.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram


Atomic Radius
175 pm
Atomic Volume
Covalent Radius
167 pm
Metallic Radius
Ionic Radius
107 pm
Crystal Radius
121 pm
Van der Waals radius
231 pm
8.55 g/cm³
Boiling Point
2,835 K
Melting Point
1,685 K
Electrons per shell2, 8, 18, 28, 8, 2
0.8854697492975 eV/particle
Proton Affinity
Electron Affinity
Ionization Potential
5.93905 eV/particle
Heat of Vaporization
291 kJ/mol
Heat of Fusion
Heat of Formation
290.4 kJ/mol
Molar Heat Capacity
28.16 J/(mol K)
Specific Heat Capacity
0.173 J/(g⋅K)
Thermal Conductivity
10.7 W/(m K)
Gas Basicity
Dipole Polarizability
163 a₀
C6 Dispersion Coefficient
Oxidation States2, 3
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.59 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Xe] 4f10 6s2
Magnetic Ordering
Magnetic Susceptibility
Poisson Ratio
Shear Modulus
Young's Modulus
Alternate Names
Adiabatic Index
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Magnetic Susceptibility
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
CategoryLanthanides, Lanthanides
CAS Group
Glawe Number24
Mendeleev Number31
Pettifor Number25
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Decay Mode
Abundance in Earth's crust
5.2 mg/kg
Abundance in Oceans
0.00000091 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe2×10-7%

Isotopes of Dysprosium

Stable Isotopes
156Dy 158Dy 160Dy 161Dy 162Dy 163Dy 164Dy
Unstable Isotopes
138Dy 139Dy 140Dy 141Dy 142Dy 143Dy 144Dy 145Dy 146Dy 147Dy 148Dy 149Dy 150Dy 151Dy 152Dy 153Dy 154Dy 155Dy 157Dy 159Dy 165Dy 166Dy 167Dy 168Dy 169Dy 170Dy 171Dy 172Dy 173Dy


French chemist Paul Émile Lecoq de Boisbaudran, while working with holmium oxide, separated dysprosium oxide from it in Paris in 1886. His procedure for isolating the dysprosium involved dissolving dysprosium oxide in acid, then adding ammonia to precipitate the hydroxide. It was not isolated in pure form until the development of ion exchange techniques in the 1950s. From the Greek word dysprositos, meaning hard to get at

DiscoverersPaul Émile Lecoq de Boisbaudran
Discovery LocationFrance
Discovery Year1886
Name OriginGreek: dysprositos (hard to get at).
Dysprosium is considered to be moderately toxic
Naturally occurring dysprosium is composed of 7 isotopes


Dysprosium oxide-nickel cermets are used in neutron-absorbing control rods in nuclear reactors. Dysprosium is used in data storage applications such as compact discs and hard discs. It is also used in dosimeters for measuring ionizing radiation. Dysprosium iodide and dysprosium bromide are used in high intensity metal-halide lamps. Its uses are limited to the experimental and esoteric.


Usually found with erbium, holmium and other rare earths in some minerals such as monazite sand, which is often 50% rare earth by weight.