Holmium
Relatively soft and malleable silvery-white metallic element, which is stable in dry air at room temperature. It oxidizes in moist air and at high temperatures. It belongs to the lanthanoids. A rare-earth metal, it is found in the minerals monazite and gadolinite. It possesses unusual magnetic properties. One natural isotope, Ho-165 exists, six radioisotopes exist, the most stable being Ho-163 with a half-life of 4570 years. Holmium is used in some metal alloys, it is also said to stimulate the metabolism. Discovered by Per Theodor Cleve and J.L. Soret in Switzerland in 1879. The name homium comes from the Greek word Holmia which means Sweden. While all holmium compounds should be considered highly toxic, initial evidence seems to indicate that they do not pose much danger. The metal's dust however, is a fire hazard.
Gallery

Unknown authorUnknown author, CC BY 1.0 <https://creativecommons.org/licenses/by/1.0>, via Wikimedia Commons, source: https://images-of-elements.com/holmium.php

Physical Propertiesmass · density · phase · crystal
Atomic Mass
164.9303Da
Density
8.8000g/cm³
Phase (STP)
Solid
Melting Point
1745.2K
Boiling Point
2973.2K
Molar Heat
0.1650J/(mol·K)
Crystal Structure
HEX
Lattice Constant
3.580Å
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
175.00pm
Covalent
166.00pm
Van der Waals
230.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[Xe] 4f11 6s2
Electron Shells
2, 8, 18, 29, 8, 2
Electronegativity
1.23Pauling
Electron Affinity
—
1st Ionization Energy
6.0kJ/mol
Oxidation States
+3
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f11 6s2Short: [Xe] 4f11 6s2
Ionization Energies (67 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Log scale · ppm = parts per million by mass
Biological Role
No known biological role.
Discovery
Discovered By
J.L. Soret
Named By
—
Year
1878
Nuclear Data
Known Isotopes
39
Stable Isotopes
1
Stable Mass Numbers
165
Natural isotopic abundance (IUPAC recommended values)
Isotopes of Ho39 known
| Nuclide | Z | N | Mass (AMU) | Half-life | Decay | Jπ | Abundance |
|---|---|---|---|---|---|---|---|
| 140Ho | 67 | 73 | 139.968526 | 6.00 ms | p, β⁺, β⁺p | 8+ | — |
| 141Ho | 67 | 74 | 140.963108 | 4.10 ms | p (1%), β⁺, β⁺p | 7/2- | — |
| 142Ho | 67 | 75 | 141.960010 | 400 ms | β⁺ (1%), β⁺p, p (0%) | 7- | — |
| 165Hostable | 67 | 98 | 164.930329 | Stable | stable (1%) | 7/2- | 10000.0000% |
| 176Ho | 67 | 109 | 175.957713 | Unknown | β⁻, β⁻n | 4+ | — |
| 177Ho | 67 | 110 | 176.961052 | Unknown | β⁻ (1%), n | 7/2- | — |
| 178Ho | 67 | 111 | 177.965507 | Unknown | β⁻, β⁻n | 2+ | — |