#67 / 118
67Ho164.93
Lanthanides (Rare Earths)solid at STPF-block

Holmium

Group: f-blockPeriod: 6Standard Atomic Weight: 164.93 u

Why is Holmium in this position?

Understanding the scientific rationale behind Holmium's position in the periodic table:

Group Assignment
Group Lanthanide / Actinide

Lanthanide series element filling the 4f subshell.

Period Assignment
Period 6

Belongs to Period 6 because its outermost electrons occupy n=6.

Orbital Block
F-block

Belongs to the f-block because valence electrons fill 4f orbitals (4f¹¹ 6s²).

Chemical Category
Lanthanides (Rare Earths)

Classified as a lanthanide rare earth metal with record magnetic moment.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 29, 8, 2]

Bohr Atomic Shell Model(2, 8, 18, 29, 8, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

67 Protons (p⁺)98 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 18Shell M: Electron 2 of 18Shell M: Electron 3 of 18Shell M: Electron 4 of 18Shell M: Electron 5 of 18Shell M: Electron 6 of 18Shell M: Electron 7 of 18Shell M: Electron 8 of 18Shell M: Electron 9 of 18Shell M: Electron 10 of 18Shell M: Electron 11 of 18Shell M: Electron 12 of 18Shell M: Electron 13 of 18Shell M: Electron 14 of 18Shell M: Electron 15 of 18Shell M: Electron 16 of 18Shell M: Electron 17 of 18Shell M: Electron 18 of 18NShell N: Electron 1 of 29Shell N: Electron 2 of 29Shell N: Electron 3 of 29Shell N: Electron 4 of 29Shell N: Electron 5 of 29Shell N: Electron 6 of 29Shell N: Electron 7 of 29Shell N: Electron 8 of 29Shell N: Electron 9 of 29Shell N: Electron 10 of 29Shell N: Electron 11 of 29Shell N: Electron 12 of 29Shell N: Electron 13 of 29Shell N: Electron 14 of 29Shell N: Electron 15 of 29Shell N: Electron 16 of 29Shell N: Electron 17 of 29Shell N: Electron 18 of 29Shell N: Electron 19 of 29Shell N: Electron 20 of 29Shell N: Electron 21 of 29Shell N: Electron 22 of 29Shell N: Electron 23 of 29Shell N: Electron 24 of 29Shell N: Electron 25 of 29Shell N: Electron 26 of 29Shell N: Electron 27 of 29Shell N: Electron 28 of 29Shell N: Electron 29 of 29OShell O: Electron 1 of 8Shell O: Electron 2 of 8Shell O: Electron 3 of 8Shell O: Electron 4 of 8Shell O: Electron 5 of 8Shell O: Electron 6 of 8Shell O: Electron 7 of 8Shell O: Electron 8 of 8PShell P: Electron 1 of 2Shell P: Electron 2 of 2HoZ = 67

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):18 / 18 electrons (100%)
Shell N (n=4):29 / 32 electrons (91%)
Shell O (n=5):8 / 50 electrons (16%)
Shell P (n=6):2 / 72 electrons (3%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹¹ 5s² 5p⁶ 6s²

Neutral ground state configuration. Valence electrons: 13.

Atomic & Quantum Properties

Electronegativity (Pauling)1.23 Pauling
1st Ionization Energy581 kJ/mol
Electron Affinity-50 kJ/mol
Atomic Radius (empirical)175 pm
Common Oxidation States+3
Crystal StructureHCP

Physical & Thermal Properties

Density at STP8.79 g/cm³
Melting Point1474 °C (1747 K)
Boiling Point2700 °C (2973 K)
Magnetic OrderingParamagnetic
Discovery Year1878
Discovered ByPer Teodor Cleve & Marc Delafontaine

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Holmium-YAG (Ho:YAG) 2.1 μm surgical laser for laser lithotripsy (pulverizing kidney stones)
  • High-field magnetic flux concentrator pole pieces in superconducting research magnets
  • Yellow and peach-pink decorative glass colorant
  • Single-atom digital data storage bits (IBM research)
Occurrence in Nature

Extracted in small quantities from monazite, bastnäsite, and xenotime mineral sands.

Etymology & Name Origin

From 'Holmia', the Latin name for Stockholm, Sweden

Important Chemical Compounds
Ho₂O₃ (Holmium oxide)
Ho:YAG (Holmium laser crystal)
HoCl₃ (Holmium chloride)
Interesting Chemical Facts
  • Holmium possesses the highest magnetic moment of any element on the periodic table (10.6 µB), enabling the strongest artificial static magnetic fields.
  • In 2017, IBM scientists successfully used a single atom of holmium to store a bit of digital data, the ultimate limit of computer miniaturization.
  • Ho:YAG surgical lasers emit at 2.1 microns, an infrared wavelength absorbed strongly by water that vaporizes tissue with sub-millimeter precision.
Safety & Handling Note

Low physiological toxicity; metal powder is combustible.