LanthanideElement 66 · f-block

Dysprosium (Dy)

Dysprosium (Dy) is a lanthanide with atomic number 66 and a standard atomic weight of 162.50. At room temperature it is a solid that melts at 1,412 °C and boils at 2,567 °C.

66DyDysprosium162.50

Atomic number

protons

Atomic weight

162.50

CIAAW 2024

Melting point

1,412 °C

1,685.15 K

Boiling point

2,567 °C

2,840.15 K

Density

8.55 g/cm³

near room temperature

Electronegativity

1.22

Pauling scale

State at 25 °C

Solid

Discovered

1886

France

Dysprosium at a glance

Identity

Symbol	Dy
Atomic number (Z)	66
Atomic weight	162.50 ± 0.01 (CIAAW 2024)
Category	Lanthanide
Group	— (f-block: lanthanide series)
Period	6
Block	f-block
CAS number	7429-91-6

Atomic properties

Electron configuration	[Xe] 4f¹⁰ 6s² Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 5s² 5p⁶ 6s²
Electrons per shell	2, 8, 18, 28, 8, 2
Oxidation states	+3 Less common: 0, +1, +2, +4
Electronegativity (Pauling)	1.22
First ionisation energy	5.939 eV (573 kJ/mol) 2nd: 11.647 eV · 3rd: 22.89 eV
Electron affinity	0.352 eV
Atomic radius (empirical)	175 pm
Covalent radius	167 pm
Van der Waals radius	231 pm

Physical properties

State at 25 °C	Solid
Melting point	1,412 °C · 2,573.6 °F · 1,685.15 K
Boiling point	2,567 °C · 4,652.6 °F · 2,840.15 K
Density	8.55 g/cm³
Specific heat capacity	0.173 J/(g·K)
Thermal conductivity	10.7 W/(m·K)
Crystal structure	Hexagonal

Isotopes & abundance

Natural occurrence	Primordial
Radioactive	No
Natural isotopes (abundance)	¹⁶⁴Dy 28.26%, ¹⁶²Dy 25.475%, ¹⁶³Dy 24.896%, ¹⁶¹Dy 18.889%, ¹⁶⁰Dy 2.329%, ¹⁵⁸Dy 0.095%
Stable isotopes	7
Known isotopes	39
Abundance in Earth's crust	5.2 mg/kg
Abundance in seawater	0.00000091 mg/L

Atomic weights: CIAAW Abridged Standard Atomic Weights 2024. Other properties: standard reference compilations, checked October 2026; predicted values are marked.

Dysprosium electron configuration

Dysprosium has 66 electrons. Written in short form, its ground-state configuration is [Xe] 4f¹⁰ 6s² — the electrons of the noble gas xenon, plus 4f¹⁰ 6s².Written out in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 5s² 5p⁶ 6s².

4f↑↓↑↓↑↓↑↑↑↑

6s↑↓

Discovery and name

Discovered

1886 — Paul-Émile Lecoq de Boisbaudran · France.

Name

Greek dysprositos, hard to get at.

Known for

Added to neodymium magnets so they keep their magnetism at high temperatures, as in electric-vehicle motors.

Isotopes of dysprosium

Naturally occurring dysprosium is a mix of 7 isotopes. Each has 66 protons; they differ in the number of neutrons:

Isotope	Protons	Neutrons	Natural abundance	Stability
¹⁶⁴Dy	66	98	28.26%	stable
¹⁶²Dy	66	96	25.475%	stable
¹⁶³Dy	66	97	24.896%	stable
¹⁶¹Dy	66	95	18.889%	stable
¹⁶⁰Dy	66	94	2.329%	stable
¹⁵⁸Dy	66	92	0.095%	stable
¹⁵⁶Dy	66	90	0.056%	stable

39 isotopes of dysprosium are known in our data set (half-lives as published in nuclear data tables).

Dysprosium and its neighbours in the lanthanide series

Neighbouring elements in the same f-block series:

Element	Z	Atomic weight	Melting point	Boiling point	Density	Electronegativity
Europium	63	151.96	822 °C	1,529 °C	5.24 g/cm³	1.2
Gadolinium	64	157.25	1,313 °C	3,273 °C	7.9 g/cm³	1.2
Terbium	65	158.93	1,359 °C	3,230 °C	8.23 g/cm³	1.1
Dysprosium	66	162.50	1,412 °C	2,567 °C	8.55 g/cm³	1.22
Holmium	67	164.93	1,472 °C	2,700 °C	8.8 g/cm³	1.23
Erbium	68	167.26	1,529 °C	2,868 °C	9.07 g/cm³	1.24
Thulium	69	168.93	1,545 °C	1,950 °C	9.321 g/cm³	1.25

Frequently asked questions

6 answers

What is the atomic mass of dysprosium?

The standard atomic weight of dysprosium is 162.50 ± 0.01 (CIAAW 2024), so one mole weighs about 162.50 grams.

How many protons, neutrons and electrons does dysprosium have?

A neutral dysprosium atom has 66 protons and 66 electrons. Its most common isotope, dysprosium-164, has 98 neutrons.

What is the electron configuration of dysprosium?

[Xe] 4f¹⁰ 6s² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 5s² 5p⁶ 6s²).

What are the melting and boiling points of dysprosium?

Dysprosium melts at 1,412 °C (2,573.6 °F) and boils at 2,567 °C (4,652.6 °F).

Is dysprosium a metal?

Dysprosium is a metal. It is in the f-block, period 6, and is a solid at room temperature.

Who discovered dysprosium?

1886 — Paul-Émile Lecoq de Boisbaudran (France).