Erbium
[Xe] 4f¹² 6s² · 2 · 8 · 18 · 30 · 8 · 2
The lanthanide that long-haul optical communication rests on: the erbium-doped fibre amplifier carries a signal across an ocean without ever converting it to electricity.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 68
- Atomic mass
- 167.259 а.е.м.
- Electron configuration
- [Xe] 4f¹² 6s²
- Electrons per shell
- 2 · 8 · 18 · 30 · 8 · 2
- Block
- f-block
- Group
- no data
- Period
- 6
- Electronegativity (Pauling)
- 1.24
- Electronegativity (Allen)
- 1.11
- Atomic radius
- 235 pm
- Covalent radius
- 189 pm
- Van der Waals radius
- 235 pm
- Ionisation energy 1
- 589.3 kJ/mol
- Ionisation energy 2
- 1 150 kJ/mol
- Ionisation energy 3
- 2 194 kJ/mol
- Ionisation energy 4
- 4 120 kJ/mol
- Electron affinity
- 50 kJ/mol
- Common oxidation states
- +3
- Oxidation states
- +2, +3
Physical properties
- State at 25 °C
- solid
- Density
- 9.066 g/cm³
- Melting point
- 1 802 K · 1 528.9 °C
- Boiling point
- 3 141 K · 2 867.9 °C
- Speed of sound
- 2 830 m/s
Thermal properties
- Heat of fusion
- 19.9 kJ/mol
- Heat of vaporisation
- 280 kJ/mol
- Specific heat capacity
- 0.168 J/(g·K)
- Thermal conductivity
- 14.5 W/(m·K)
Mechanical properties
- Young's modulus
- 69.9 GPa
- Shear modulus
- 28.3 GPa
- Bulk modulus
- 44.4 GPa
- Poisson ratio
- 0.24
- Mohs hardness
- no data
- Brinell hardness
- 814 MPa
Electrical and magnetic properties
- Electrical resistivity
- 860 nΩ·m
- Magnetic ordering
- paramagnetic
- Curie point
- 19 K
- Néel point
- no data
- Superconducting point
- no data
Crystal structure
- Crystal structure
- hexagonal close-packed (hcp)
- Lattice constants
- a = 355.92 pm · c = 558.5 pm
Abundance
- In the crust
- 3.5 mg/kg
- In the ocean
- 8.7·10⁻⁷ mg/L
- In the universe
- 0.2 mg/kg
- In the human body
- 0 mg/kg
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 162Er | 0.139 % | stable | — |
| 164Er | 1.601 % | stable | — |
| 166Er | 33.503 % | stable | — |
| 167Er | 22.869 % | stable | — |
| 168Er | 26.978 % | stable | — |
| 170Er | 14.91 % | stable | — |
Six stable isotopes. Erbium-169 is used in radiosynovectomy of small joints.
Discovery
- Year of discovery
- 1843
- Discovered by
- Carl Gustaf Mosander
- Where
- Sweden
- Origin of the name
- after Ytterby, the village in Sweden
History
Mosander isolated erbium along with terbium from the yttrium earth in 1843. The name comes from the same Swedish village of Ytterby.
Where it occurs
3.5 mg/kg of the crust. It is recovered from xenotime and ion-adsorption clays.
How it is produced
By separating heavy rare earths. Optical fibre is the main consumer.
Role in living things
No biological role.
Safety
Of low toxicity. The powder is pyrophoric, and inhaled oxide dust irritates the airways.
Uses
- Erbium-doped fibre amplifiers — the backbone of transoceanic links
- Er:YAG lasers in dermatology and dentistry, whose light is absorbed by tissue water
- Pink colouring of glass and glazes
- Alloying vanadium to soften it
Curiosities
- Every message crossing an ocean by fibre is amplified by erbium, roughly every 80 kilometres.
- Erbium emits at exactly 1.55 µm — precisely where silica fibre loses least.
- Pink glass and glazes are coloured with erbium.
- The erbium amplifier, invented in 1987, is what made the modern internet economically possible.