Lithium
alkali metal · period 2 · group 1 (alkali metals (and hydrogen)) · s-block
Lithium (from Greek: λίθος, romanized: lithos, lit. 'stone') is a chemical element with the symbol Li and atomic number 3.
What the numbers say
At standard temperature and pressure Lithium is a solid, sitting in period 2, group 1 of the s-block.
Its melting point of 454 K (181 °C) is the 85th highest of the 110 elements with a measured value — mid-range among the elements.
At 0.535 g/cm³ it is the 85th densest of 96 elements with a quoted density.
Pauling electronegativity is 0.98. Paired with oxygen (3.44) that is a difference of 2.46, 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.
First identified in 1817.
Crystal structure
Solid Lithium 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 Li — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 1
Properties
| Atomic number | 3 |
|---|---|
| Atomic mass | 6.94 u |
| Series | alkali metal |
| Group | 1 |
| Period | 2 |
| Block | s-block |
| Phase at STP | Solid |
| Density | 0.535 g/cm³ |
| Melting point | 453.65 K (181 °C) |
| Boiling point | 1603 K (1330 °C) |
| Electronegativity (Pauling) | 0.98 |
| Electron configuration | [He] 2s¹ |
| Crystal structure | Body-centered Cubic |
| Oxidation states | 1 |
| Discovered | 1817 |
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See Li in context with all 118 elements.
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