What is the noble-gas shorthand for dysprosium?

The abbreviated (noble-gas) notation is [Xe] 4f¹⁰ 6s², where [Xe] represents the filled xenon core (54 electrons).

Does dysprosium have an exception to the Aufbau principle?

No. Unlike gadolinium (Gd, 4f⁷ 5d¹), dysprosium follows regular Aufbau filling: the 4f subshell simply accumulates 10 electrons with no promotion to 5d. The half-filled stability that drives Gd's exception does not apply at 4f¹⁰.

How many unpaired electrons does dysprosium have?

Dysprosium has four unpaired electrons in its 4f subshell. By Hund's rule, the 10 electrons fill all seven 4f orbitals singly first (7 up-spins), then three orbitals receive a second electron (3 paired). That leaves 7 − 3 = 4 unpaired spins.

Why is dysprosium important in permanent magnets?

Dysprosium's large magnetic moment (≈10.6 μ_B from four unpaired 4f electrons) and strong spin-orbit coupling increase the coercivity of neodymium-iron-boron (NdFeB) magnets at elevated temperatures. Without Dy, NdFeB magnets lose coercivity above ~80 °C, limiting use in electric-vehicle motors and wind turbines.

What oxidation state does dysprosium usually form?

Dysprosium primarily forms the +3 ion (Dy³⁺) by losing both 6s electrons and one 4f electron. A rare +4 state has been observed in some solid-state compounds but is not common in solution chemistry.

Why was dysprosium historically difficult to isolate?

The name dysprosium comes from the Greek dysprositos (hard to get). Lanthanides have nearly identical ionic radii and chemistry, making separation by classical precipitation extremely tedious. Pure dysprosium was not isolated until 1950 using ion-exchange chromatography.

Dysprosium Electron Configuration

Name: Dysprosium Electron Configuration
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Reference for dysprosium (Dy, Z=66): full configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 5s² 5p⁶ 6s², noble-gas shorthand [Xe] 4f¹⁰ 6s², orbital box diagram, and key applications.

Z = 66 Dy Dysprosium

Dysprosium — Electron Configuration

Atomic number 66 · Lanthanide series · Period 6, f-block · Rare earth element

[Xe] 4f¹⁰ 6s² 66 electrons 4 unpaired e⁻ +3 typical

Subshell Breakdown

Subshell	Type	Electrons	Max Capacity	Notation
1s	s orbital, shell n=1	2	2	1s²
2s	s orbital, shell n=2	2	2	2s²
2p	p orbitals, shell n=2	6	6	2p⁶
3s	s orbital, shell n=3	2	2	3s²
3p	p orbitals, shell n=3	6	6	3p⁶
3d	d orbitals, shell n=3	10	10	3d¹⁰
4s	s orbital, shell n=4	2	2	4s²
4p	p orbitals, shell n=4	6	6	4p⁶
4d	d orbitals, shell n=4	10	10	4d¹⁰
5s	s orbital, shell n=5	2	2	5s²
5p	p orbitals, shell n=5	6	6	5p⁶
6s	s orbital, shell n=6 (fills before 4f)	2	2	6s²
4f	f orbitals, shell n=4 (valence, fills last)	10	14	4f¹⁰
Total		66

Full Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 5s² 5p⁶ 6s²

All subshells written explicitly; 66 electrons total.

Noble-Gas Shorthand

[Xe] 4f¹⁰ 6s²

[Xe] = 54-electron xenon core (1s² through 5p⁶).

Shell Fill Summary

Shell 1 (n=1) — 1s² 2 / 2 electrons (100%)

Shell 2 (n=2) — 2s² 2p⁶ 8 / 8 electrons (100%)

Shell 3 (n=3) — 3s² 3p⁶ 3d¹⁰ 18 / 18 electrons (100%)

Shell 4 (n=4) — 4s² 4p⁶ 4d¹⁰ 4f¹⁰ 32 / 32 electrons (100%)

Shell 5 (n=5) — 5s² 5p⁶ 8 / 50 electrons (16%)

Shell 6 (n=6) — 6s² 2 / 72 electrons (3%)

Shell 4 can hold up to 32 electrons (4s + 4p + 4d + 4f). Dysprosium fills all 32, completing this shell. Shell 5 holds 8 of a possible 50 electrons; shell 6 holds only the 6s² pair.

The Xenon Core — [Xe]

The first 54 electrons of dysprosium match the complete electron configuration of xenon (Z=54):

[Xe] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶

The remaining 12 electrons — 4f¹⁰ 6s² — determine dysprosium's chemistry, magnetic moment, and oxidation behavior.

Regular Aufbau Filling — No Exception

Some lanthanides deviate from Aufbau filling to reach a half- or fully-filled f subshell (e.g., Gd: [Xe] 4f⁷ 5d¹ 6s²). Dysprosium does not. Its 4f¹⁰ configuration is reached by straightforward sequential filling with no 5d promotion.

Tb [Xe] 4f⁹ 6s² Dy [Xe] 4f¹⁰ 6s² Ho [Xe] 4f¹¹ 6s²

Orbital Box Diagram

Each box represents one orbital. Opposing arrows = paired electrons. A single up arrow = unpaired electron. Core subshells (part of [Xe]) are shown collapsed for readability.

[Xe]

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ — 54 core electrons (all paired)

2 electrons (paired) — fills before 4f in free atom

10 electrons across 7 orbitals: 3 paired + 4 unpaired (Hund's rule) — 4 unpaired spins

Hund's rule fills all seven 4f orbitals with one electron each (spins up) before any orbital receives a second electron. For 4f¹⁰: orbitals 1–7 each get one up-spin (7 electrons), then orbitals 1–3 each get a second down-spin electron (3 more), totaling 10. Orbitals 4–7 retain their single unpaired electron.

This gives dysprosium 4 unpaired 4f electrons and a magnetic moment of approximately 10.6 μ_B — one of the highest of any element.

Quantum Numbers for All 66 Electrons

e⁻ #	n	l	mₗ	mₛ	Subshell
1	1	0	0	+½	1s
2	1	0	0	−½	1s
3	2	0	0	+½	2s
4	2	0	0	−½	2s
5	2	1	-1	+½	2p
6	2	1	-1	−½	2p
7	2	1	0	+½	2p
8	2	1	0	−½	2p
9	2	1	1	+½	2p
10	2	1	1	−½	2p
11	3	0	0	+½	3s
12	3	0	0	−½	3s
13	3	1	-1	+½	3p
14	3	1	-1	−½	3p
15	3	1	0	+½	3p
16	3	1	0	−½	3p
17	3	1	1	+½	3p
18	3	1	1	−½	3p
19	4	0	0	+½	4s
20	4	0	0	−½	4s
21	3	2	-2	+½	3d
22	3	2	-2	−½	3d
23	3	2	-1	+½	3d
24	3	2	-1	−½	3d
25	3	2	0	+½	3d
26	3	2	0	−½	3d
27	3	2	1	+½	3d
28	3	2	1	−½	3d
29	3	2	2	+½	3d
30	3	2	2	−½	3d
31	4	1	-1	+½	4p
32	4	1	-1	−½	4p
33	4	1	0	+½	4p
34	4	1	0	−½	4p
35	4	1	1	+½	4p
36	4	1	1	−½	4p
37	5	0	0	+½	5s
38	5	0	0	−½	5s
39	4	2	-2	+½	4d
40	4	2	-2	−½	4d
41	4	2	-1	+½	4d
42	4	2	-1	−½	4d
43	4	2	0	+½	4d
44	4	2	0	−½	4d
45	4	2	1	+½	4d
46	4	2	1	−½	4d
47	4	2	2	+½	4d
48	4	2	2	−½	4d
49	5	1	-1	+½	5p
50	5	1	-1	−½	5p
51	5	1	0	+½	5p
52	5	1	0	−½	5p
53	5	1	1	+½	5p
54	5	1	1	−½	5p
55	6	0	0	+½	6s
56	6	0	0	−½	6s
57	4	3	-3	+½	4f
58	4	3	-2	+½	4f
59	4	3	-1	+½	4f
60	4	3	0	+½	4f
61	4	3	1	+½	4f
62	4	3	2	+½	4f
63	4	3	3	+½	4f
64	4	3	-3	−½	4f
65	4	3	-2	−½	4f
66	4	3	-1	−½	4f

n = principal quantum number; l = azimuthal (0→s, 1→p, 2→d, 3→f); mₗ = magnetic; mₛ = spin. Electrons 57–66 are the 4f¹⁰ subshell: the first seven (57–63) carry spin +½; electrons 64–66 pair up the first three orbitals with spin −½, leaving orbitals mₗ = 0, 1, 2, 3 with unpaired spins.

Identity

SymbolDy Atomic number66 Atomic mass162.500 u SeriesLanthanide Period6 Blockf-block Name originGreek: dysprositos

Physical Properties

State (25 °C)Solid Melting point1412 °C Boiling point2567 °C Density8.55 g/cm³ ColorSilvery white Crystal structureHCP

Electronic Properties

Valence subshells4f¹⁰ 6s² Unpaired electrons4 (in 4f) Magnetic moment≈10.6 μ_B Common oxidation state+3 Rare oxidation state+4 (solid state) 1st ionization energy573.0 kJ/mol

Key Applications

NdFeB permanent magnets: 1–3% Dy addition raises coercivity at high temperatures, enabling use in EV motors and wind turbine generators.
Nuclear reactor control rods: dysprosium has a high neutron absorption cross-section, making it useful in reactor control.
Magnetostrictive alloys: Terfenol-D (Tb-Dy-Fe) converts electrical energy to mechanical displacement with high efficiency.
Data storage research: DyFe films have been investigated as magneto-optical recording media.
Historically difficult to isolate — lanthanide separation required ion-exchange chromatography; first pure sample obtained in 1950.

Summary

How it works

The Aufbau principle fills subshells from lowest to highest energy: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f.
Dysprosium's 66 electrons fill the xenon core (1s² through 5p⁶, 54 electrons) and then add 4f¹⁰ 6s².
The 6s subshell fills before 4f in the free atom because it sits at lower energy at low Z; the 4f subshell is held close to the nucleus by poor shielding.
Dysprosium follows regular Aufbau filling in 4f — no exception like gadolinium (Gd, 4f⁷ 5d¹). The 4f¹⁰ configuration holds 10 electrons across 7 orbitals.
Hund's rule distributes the 10 4f electrons: seven orbitals each receive one spin-up electron first, then three orbitals receive a second (spin-down) electron.
This leaves four unpaired 4f electrons and gives dysprosium one of the largest magnetic moments of any element (10.6 μ_B).
Noble-gas notation [Xe] 4f¹⁰ 6s² abbreviates the 54-electron xenon core, exposing the valence subshells responsible for Dy's chemistry.

Use cases

Quick reference for chemistry homework or exam review on lanthanide electron filling.
Understand why dysprosium is added to NdFeB magnets — its large magnetic moment boosts coercivity at high temperatures.
Visualize how the 4f subshell fills across the lanthanide series from cerium to lutetium.
Verify quantum numbers for any of dysprosium's 66 electrons.
Compare dysprosium to adjacent lanthanides (terbium, holmium) to see 4f filling trends.
Teaching aid for the Aufbau principle and f-block element configurations in advanced chemistry courses.
Understand dysprosium's primary +3 oxidation state from its valence configuration.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu