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Holmium (Ho)

Holmium is a chemical element of the periodic table with chemical symbol Ho and atomic number 67 with an atomic weight of 164.93 u and is classed as lanthanide. Holmium is solid at room temperature.

Holmium in the periodic table

Atomic number67
AppearanceSilvery white
Color Silver
Number of protons67 p+
Number of neutrons98 n0
Number of electrons67 e-
From Wikipedia, the free encyclopediaHolmium 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.

Physical properties

Phase at STPSolid
Density8.79 g/cm3
Atomic weight164.93 u

Thermal properties

Melting point1734 K
1460.85 °C
2661.53 °F
Boiling point2873 K
2599.85 °C
4711.73 °F
Heat of vaporization251.04 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.23
Electron affinity32.61 kJ/mol
Oxidation states0, +1, +2, +3
(a basic oxide)
Ionization energies
  1. 581 kJ/mol
  2. 1140 kJ/mol
  3. 2204 kJ/mol
  4. 4100 kJ/mol

Electron configuration for holmium

Electron configuration
Shorthand configuration
[Xe] 4f11 6s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f11 5s2 5p6 6s2
Electron configuration chart
Electrons per shell2, 8, 18, 29, 8, 2
Valence electrons 2
Valency electrons 3
Bohr model
HolmiumElectron shell for Holmium, created by Injosoft ABHo
Figure: Shell diagram of Holmium (Ho) atom.
Orbital Diagram

The history of Holmium

DiscoveryJacques-Louis Soret, Marc Delafontaine (1878)
First isolationPer Teodor Cleve (1879)
Named byPer Teodor Cleve (1879)
Discovery of holmium
Holmium was discovered through isolation by Swedish chemist Per Theodor Cleve and independently by Jacques-Louis Soret and Marc Delafontaine, who observed it spectroscopically in 1878. Its oxide was first isolated from rare-earth ores by Cleve in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm. As well, Per Teodor Cleve independently discovered the element while he was working on erbia earth (erbium oxide), and was the first to isolate it. Using the method developed by Carl Gustaf Mosander, Cleve first removed all of the known contaminants from erbia. The result of that effort was two new materials, one brown and one green. He named the brown substance holmia (after the Latin name for Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be the holmium oxide, and thulia was thulium oxide. Like many other lanthanides, holmium is found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion-exchange techniques.


List of unique identifiers for Holmium in various chemical registry databases
CAS Number7440-60-0
ChemSpider ID22424
EC number231-169-0
PubChem CID Number23988