ElementsWhat is holmium?
Holmium is a soft, silvery metal of the lanthanide row. It has the strongest magnetic moment of any natural element.
What is holmium used for?
Medical and dental lasers, and pole pieces for very strong magnets.
Where the name comes from
From Holmia, the Latin name for Stockholm.
Key facts
- Symbol
- Ho
- Atomic number
- 67
- Atomic mass
- 164.93033 u
- Family
- Lanthanide
- Period
- 6
- Group
- none (f-block)
- Block
- f
- State at room temperature
- Solid
- Melting point
- 1,474 °C (1,747 K, 2,685 °F)
- Boiling point
- 2,700 °C (2,973 K, 4,892 °F)
- Density
- 8.8 g/cm³
- Electrons per shell
- 2, 8, 18, 29, 8, 2
- Electron configuration
- [Xe]6s2 4f11
- Common oxidation states
- +3
- Electronegativity (Pauling)
- 1.23
- First ionisation energy
- 6.022 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- 216 pm
- Discovered
- 1878
Place in the periodic table
Holmium is element number 67. It sits in period 6 (row 6) of the periodic table, in the separate row of lanthanides drawn below the main table, and belongs to the f-block. Just before it comes dysprosium (66), and just after it comes erbium (68).
Family: Lanthanides.
Physical properties
At room temperature holmium is a solid. It melts at 1,474 °C and boils at 2,700 °C, so it stays liquid over a range of 1,226 degrees. Its density is 8.8 grams per cubic centimetre, so a one-litre block would weigh about 8.8 kilograms. By density it ranks 35th among the 96 elements with a measured value.
Inside the atom
An atom of holmium has 67 protons in its nucleus and, when neutral, 67 electrons around it. The electrons are arranged in 6 shells: 2, 8, 18, 29, 8, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Xe]6s2 4f11.
Its electronegativity on the Pauling scale is 1.23. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 6.022 electronvolts (about 581 kilojoules per mole). One mole of holmium weighs 164.93033 grams, so a single gram contains about 3.65 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains holmium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.