Holmium (Ho)
Lanthanide
Holmium holds the record for the strongest magnetic moment of any natural element, concentrating magnetic flux in specialist magnets. Its lasers cut precisely through kidney stones in modern surgery.
Position on the periodic table
Atomic properties
| Atomic number | 67 |
|---|---|
| Atomic mass | 164.93 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f11 |
| Noble gas shorthand | [Xe] 4f11 6s2 |
| Electrons per shell | 2, 8, 18, 29, 8, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +3 |
| Electronegativity (Pauling) | 1.23 |
| Covalent radius (approx.) | 192 pm |
| First ionization energy | 581 kJ/mol |
| Electron affinity | 32.6 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 8.79 g/cm³ |
| Melting point | 1460.8 °C (1734 K) |
| Boiling point | 2599.8 °C (2873 K) |
| Appearance | silvery white |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of holmium
Holmium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f11, usually shortened to [Xe] 4f11 6s2. Its electrons occupy 6 shells (2, 8, 18, 29, 8, 2), placing it in period 6 of the f-block. Explore it interactively in the electron configuration calculator.
Uses of holmium
- Magnetic flux concentrators
- Surgical lasers
- Yellow-red glass colouring
- Calibration standard for spectrophotometers
Biological role: None known.
Occurrence: From monazite and ion-adsorption clays.
Common compounds of holmium
Ho2O3
Holmium(III) oxide
History and discovery
Discovered: 1878 — Marc Delafontaine. Name origin: From Holmia, the Latin name for Stockholm.
Per Teodor Cleve identified holmium in 1878; Swiss spectroscopists Delafontaine and Soret saw its lines the same year.
Safety notes
Low toxicity; standard rare-earth precautions.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Holmium
1. What is the chemical symbol of Holmium?
2. What is the atomic number of Holmium?
3. Which category does Holmium belong to?
4. What is the state of Holmium at room temperature?
5. Which period of the periodic table is Holmium in?
Holmium FAQs
What is element 67 on the periodic table?
Element 67 is holmium (symbol Ho), a soft, silvery lanthanide — one of the rare-earth metals. It was discovered in 1878 and has the highest magnetic strength of any naturally occurring element.
What is holmium used for?
Its exceptional magnetic properties make holmium useful in the strongest laboratory magnets, in certain medical and industrial lasers, and as a neutron-absorbing material in nuclear control rods.
What is the atomic number of holmium?
Holmium's atomic number is 67 — every holmium atom has 67 protons in its nucleus.
What is the symbol for holmium?
Ho. From Holmia, the Latin name for Stockholm.
Is holmium a metal, nonmetal, or metalloid?
Holmium is classified as a lanthanide.
What state is holmium at room temperature?
At about 25 °C, holmium is a solid. It melts at 1460.8 °C.
Sources & references
- Holmium — Element information — Royal Society of Chemistry
Atomic masses and element data follow current IUPAC/NIST standard values. Educational content only — for graded or laboratory work, verify against your course materials. Last reviewed July 11, 2026.
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