ELEMENTLE

Element 67 · Lanthanide

Holmium

Period 6

Holmium is a chemical element with symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve.

Three reasons Holmium stands out

  1. 1

    Used in lasers and MRI machines.

  2. 2

    Medical lasers using this element can destroy kidney stones and tumours without making a single surgical incision.

  3. 3

    It is used alongside another rare earth metal to generate the world's strongest artificially produced magnetic fields.

The strongest atomic magnetic moment

Holmium atoms carry the largest magnetic moment of any element, a feature exploited in specialized magnetic-field research. Holmium-doped lasers emit wavelengths strongly absorbed by water, allowing surgeons to cut tissue or fragment kidney stones with tightly delivered pulses.

Recognizing Holmium in Elementle

If Holmium is the mystery element, guesses below atomic number 67 point up and guesses above it point down. Its symbol is Ho: a green letter matches the same position in that symbol, while a yellow letter belongs in another position.

The family clue turns green for lanthanide guesses. Compare Dysprosium (Dy), number 66 and Erbium (Er), number 68: they share the family clue, but their atomic numbers and symbols help you tell them apart.

Learn how to read the clues or play the daily element guessing game.

Holmium at a glance
Atomic number / protons67
SymbolHo
Family (Elementle)Lanthanide
Classification (PubChem)Lanthanide
Period6
GroupLanthanide / actinide series
Atomic mass (u)164.93033
Standard stateSolid
Electron configuration[Xe]6s2 4f11
Reported oxidation states+3
Electronegativity (Pauling)1.23
Atomic radius (pm)216
First ionization energy (eV)6.022
Electron affinity (eV)Not available
Density (g/cm³)8.80
Melting point1747 K (1,473.85 °C)
Boiling point2973 K (2,699.85 °C)
Discovery (PubChem)1878

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Holmium · Holmium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.