Holmium
[Xe] 4f¹¹ 6s² · 2 · 8 · 18 · 29 · 8 · 2
The element with the largest atomic magnetic moment of all, 10.6 Bohr magnetons. Holmium is used to make the strongest artificial magnetic fields and in surgical lasers.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 67
- Atomic mass
- 164.93 а.е.м.
- Electron configuration
- [Xe] 4f¹¹ 6s²
- Electrons per shell
- 2 · 8 · 18 · 29 · 8 · 2
- Block
- f-block
- Group
- no data
- Period
- 6
- Electronegativity (Pauling)
- 1.23
- Electronegativity (Allen)
- 1.1
- Atomic radius
- 216 pm
- Covalent radius
- 192 pm
- Van der Waals radius
- 216 pm
- Ionisation energy 1
- 581 kJ/mol
- Ionisation energy 2
- 1 140 kJ/mol
- Ionisation energy 3
- 2 204 kJ/mol
- Ionisation energy 4
- 4 100 kJ/mol
- Electron affinity
- 50 kJ/mol
- Common oxidation states
- +3
- Oxidation states
- +2, +3
Physical properties
- State at 25 °C
- solid
- Density
- 8.79 g/cm³
- Melting point
- 1 734 K · 1 460.9 °C
- Boiling point
- 2 993 K · 2 719.9 °C
- Speed of sound
- 2 760 m/s
Thermal properties
- Heat of fusion
- 17 kJ/mol
- Heat of vaporisation
- 265 kJ/mol
- Specific heat capacity
- 0.165 J/(g·K)
- Thermal conductivity
- 16.2 W/(m·K)
Mechanical properties
- Young's modulus
- 64.8 GPa
- Shear modulus
- 26.3 GPa
- Bulk modulus
- 40.2 GPa
- Poisson ratio
- 0.23
- Mohs hardness
- no data
- Brinell hardness
- 746 MPa
Electrical and magnetic properties
- Electrical resistivity
- 814 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 = 357.78 pm · c = 561.78 pm
Abundance
- In the crust
- 1.3 mg/kg
- In the ocean
- 2.2·10⁻⁷ mg/L
- In the universe
- 0.05 mg/kg
- In the human body
- 0 mg/kg
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 165Ho | 100 % | stable | — |
Holmium-165 is the only stable isotope. Holmium-166 is used in treating liver tumours.
Discovery
- Year of discovery
- 1878
- Discovered by
- Jacques-Louis Soret and Marc Delafontaine
- Where
- Switzerland
- Origin of the name
- from Holmia, the Latin name for Stockholm
History
Soret and Delafontaine in Geneva noticed new spectral lines in 1878, and Cleve in Sweden independently isolated the oxide in 1879. The name is from Holmia, the Latin for Stockholm.
Where it occurs
1.3 mg/kg of the crust. It is recovered from monazite and ion-adsorption clays.
How it is produced
By separating heavy rare earths, then metallothermic reduction.
Role in living things
No biological role.
Safety
Of low toxicity. Data on chronic exposure are sparse given its limited use; the powdered metal is pyrophoric.
Uses
- Ho:YAG lasers in urology for stone fragmentation and prostate surgery
- Pole pieces for generating ultra-strong magnetic fields
- Doping glass and cubic zirconia for yellow-red colour
- Wavelength standards for calibrating spectrophotometers
Curiosities
- Holmium has the largest atomic magnetic moment of any element in the table.
- The holmium laser became the standard for kidney stones: it fragments them without damaging tissue.
- Holmium oxide gives glass sharp narrow absorption bands used as a wavelength standard.
- The name comes from the Latin for Stockholm.