Europium
lanthanide · period 6 · group 3 · f-block
Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture.
What the numbers say
At standard temperature and pressure Europium is a solid, sitting in period 6, group 3 of the f-block.
Its melting point of 1099 K (826 °C) is the 60th highest of the 110 elements with a measured value — mid-range among the elements.
At 5.244 g/cm³ it is the 62nd densest of 96 elements with a quoted density.
Pauling electronegativity is 1.2. Paired with oxygen (3.44) that is a difference of 2.24, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a body-centered cubic structure — BCC packing is stronger but shows a ductile-to-brittle transition as temperature drops.
It is reported in 2 oxidation states (2, 3), which sets how many distinct compounds and phases it can form.
First identified in 1901.
Crystal structure
Solid Europium adopts a Body-centered Cubic arrangement, in the Cubic (isometric) system — axes a = b = c, angles α = β = γ = 90°. 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 Eu — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 25 · O 8 · P 2
Properties
| Atomic number | 63 |
|---|---|
| Atomic mass | 151.9641 u |
| Series | lanthanide |
| Group | 3 |
| Period | 6 |
| Block | f-block |
| Phase at STP | Solid |
| Density | 5.244 g/cm³ |
| Melting point | 1099 K (826 °C) |
| Boiling point | 1802 K (1529 °C) |
| Electronegativity (Pauling) | 1.2 |
| Electron configuration | [Xe] 4f⁷ 6s² |
| Crystal structure | Body-centered Cubic |
| Oxidation states | 2,3 |
| Discovered | 1901 |
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See Eu in context with all 118 elements.
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