Holmium
lanthanide · period 6 · group 3 · f-block
Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare-earth element. 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.
What the numbers say
At standard temperature and pressure Holmium is a solid, sitting in period 6, group 3 of the f-block.
Its melting point of 1734 K (1461 °C) is the 32nd highest of the 110 elements with a measured value — mid-range among the elements.
At 8.795 g/cm³ it is the 36th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.23. Paired with oxygen (3.44) that is a difference of 2.21, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a simple hexagonal structure — hexagonal packing offers few easy slip systems, so properties are anisotropic and formability is limited.
First identified in 1878.
Crystal structure
Solid Holmium adopts a Simple Hexagonal arrangement, in the Hexagonal system — axes a = b ≠ c, angles α = β = 90°, γ = 120°. Symmetry controls the anisotropy of stiffness and thermal expansion, and the available slip systems set how far the metal deforms before it fractures.
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Ho — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 29 · O 8 · P 2
Properties
| Atomic number | 67 |
|---|---|
| Atomic mass | 164.930332 u |
| Series | lanthanide |
| Group | 3 |
| Period | 6 |
| Block | f-block |
| Phase at STP | Solid |
| Density | 8.795 g/cm³ |
| Melting point | 1734 K (1461 °C) |
| Boiling point | 2873 K (2600 °C) |
| Electronegativity (Pauling) | 1.23 |
| Electron configuration | [Xe] 4f¹¹ 6s² |
| Crystal structure | Simple Hexagonal |
| Oxidation states | 3 |
| Discovered | 1878 |
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See Ho in context with all 118 elements.
Working with holmium in a real design?
Ask the materials chat how Ho behaves in your alloy system, what it does to weldability, and which grades to look at — with the source of every number named.