Beryllium
alkaline earth metal · period 2 · group 2 (alkaline earth metals) · s-block
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal.
What the numbers say
At standard temperature and pressure Beryllium is a solid, sitting in period 2, group 2 of the s-block.
Its melting point of 1560 K (1287 °C) is the 39th highest of the 110 elements with a measured value — mid-range among the elements.
At 1.848 g/cm³ it is the 78th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.57. Paired with oxygen (3.44) that is a difference of 1.87, 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.
It is reported in 2 oxidation states (1, 2), which sets how many distinct compounds and phases it can form.
First identified in 1797.
Crystal structure
Solid Beryllium 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 Be — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 2
Properties
| Atomic number | 4 |
|---|---|
| Atomic mass | 9.01218315 u |
| Series | alkaline earth metal |
| Group | 2 |
| Period | 2 |
| Block | s-block |
| Phase at STP | Solid |
| Density | 1.848 g/cm³ |
| Melting point | 1560 K (1287 °C) |
| Boiling point | 2742 K (2469 °C) |
| Electronegativity (Pauling) | 1.57 |
| Electron configuration | [He] 2s² |
| Crystal structure | Simple Hexagonal |
| Oxidation states | 1,2 |
| Discovered | 1797 |
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See Be in context with all 118 elements.
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