ToolFeather
LanthanideElement 70 · f-block

Ytterbium (Yb)

Ytterbium (Yb) is a lanthanide with atomic number 70 and a standard atomic weight of 173.05. At room temperature it is a solid that melts at 824 °C and boils at 1,196 °C.

Ytterbium key facts

70YbYtterbium173.05
Atomic number
70
protons
Atomic weight
173.05
CIAAW 2024
Melting point
824 °C
1,097.15 K
Boiling point
1,196 °C
1,469.15 K
Density
6.9 g/cm³
near room temperature
Electronegativity
1.1
Pauling scale
State at 25 °C
Solid
 
Discovered
1878
Switzerland

Ytterbium at a glance

Identity

SymbolYb
Atomic number (Z)70
Atomic weight173.05 ± 0.02 (CIAAW 2024)
CategoryLanthanide
Group— (f-block: lanthanide series)
Period6
Blockf-block
CAS number7440-64-4

Atomic properties

Electron configuration[Xe] 4f14 6s2
Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 6s2
Electrons per shell2, 8, 18, 32, 8, 2
Oxidation states+3
Less common: 0, +1, +2
Electronegativity (Pauling)1.1
First ionisation energy6.254 eV (603.4 kJ/mol)
2nd: 12.179 eV · 3rd: 25.053 eV
Atomic radius (empirical)175 pm
Covalent radius170 pm
Van der Waals radius226 pm

Physical properties

State at 25 °CSolid
Melting point824 °C · 1,515.2 °F · 1,097.15 K
Boiling point1,196 °C · 2,184.8 °F · 1,469.15 K
Density6.9 g/cm³
Specific heat capacity0.155 J/(g·K)
Crystal structureFace-centred cubic

Isotopes & abundance

Natural occurrencePrimordial
RadioactiveNo
Natural isotopes (abundance)174Yb 32.025%, 172Yb 21.686%, 173Yb 16.103%, 171Yb 14.086%, 176Yb 12.995%, 170Yb 2.982%
Stable isotopes7
Known isotopes38
Abundance in Earth's crust3.2 mg/kg
Abundance in seawater0.00000082 mg/L

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

Ytterbium electron configuration

Ytterbium has 70 electrons. Written in short form, its ground-state configuration is [Xe] 4f14 6s2 — the electrons of the noble gas xenon, plus 4f14 6s2.Written out in full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 6s2.

Yb
4f↑↓↑↓↑↓↑↓↑↓↑↓↑↓
6s↑↓

Discovery and name

Discovered

1878 — Jean Charles Galissard de Marignac · Switzerland.

Name

Ytterby, Sweden.

Known for

Ytterbium atomic clocks are among the most precise ever built. Also used in fibre lasers and to strengthen stainless steel.

Isotopes of ytterbium

Naturally occurring ytterbium is a mix of 7 isotopes. Each has 70 protons; they differ in the number of neutrons:

IsotopeProtonsNeutronsNatural abundanceStability
174Yb7010432.025%stable
172Yb7010221.686%stable
173Yb7010316.103%stable
171Yb7010114.086%stable
176Yb7010612.995%stable
170Yb701002.982%stable
168Yb70980.123%stable

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

Ytterbium and its neighbours in the lanthanide series

Neighbouring elements in the same f-block series:

ElementZAtomic weightMelting pointBoiling pointDensityElectronegativity
Holmium67164.931,472 °C2,700 °C8.8 g/cm³1.23
Erbium68167.261,529 °C2,868 °C9.07 g/cm³1.24
Thulium69168.931,545 °C1,950 °C9.321 g/cm³1.25
Ytterbium70173.05824 °C1,196 °C6.9 g/cm³1.1
Lutetium71174.971,663 °C3,402 °C9.84 g/cm³1.27

Frequently asked questions

6 answers
What is the atomic mass of ytterbium?
The standard atomic weight of ytterbium is 173.05 ± 0.02 (CIAAW 2024), so one mole weighs about 173.05 grams.
How many protons, neutrons and electrons does ytterbium have?
A neutral ytterbium atom has 70 protons and 70 electrons. Its most common isotope, ytterbium-174, has 104 neutrons.
What is the electron configuration of ytterbium?
[Xe] 4f¹⁴ 6s² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 6s²).
What are the melting and boiling points of ytterbium?
Ytterbium melts at 824 °C (1,515.2 °F) and boils at 1,196 °C (2,184.8 °F).
Is ytterbium a metal?
Ytterbium is a metal. It is in the f-block, period 6, and is a solid at room temperature.
Who discovered ytterbium?
1878 — Jean Charles Galissard de Marignac (Switzerland).