Gallium
post-transition metal · period 4 · group 13 · p-block
Gallium is a chemical element with the symbol Ga and atomic number 31. Discovered by French chemist Paul-Èmile Lecoq De Boisbaudran in 1875, Gallium is in group 13 of the periodic table, and has similarities to the other metals of the group (aluminium, indium, and thallium). Elemental gallium is a soft, silvery metal at standard temperature and pressure.
What the numbers say
At standard temperature and pressure Gallium is a solid, sitting in period 4, group 13 of the p-block.
Its melting point of 303 K (30 °C) is the 94th highest of the 110 elements with a measured value — mid-range among the elements.
At 5.904 g/cm³ it is the 59th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.81. Paired with oxygen (3.44) that is a difference of 1.63, which puts the bond polar covalent — oxides here tend to be semiconducting or refractory rather than salt-like.
In the solid state it takes a base orthorhombic structure.
It is reported in 3 oxidation states (1, 2, 3), which sets how many distinct compounds and phases it can form.
First identified in 1875.
Crystal structure
Solid Gallium adopts a Base Orthorhombic arrangement, in the Orthorhombic 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.
Where gallium shows up in engineering materials
1 entry in the materials library names it directly:
- Gallium nitride (GaN) — Wide-bandgap semiconductor
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Ga — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 3
Properties
| Atomic number | 31 |
|---|---|
| Atomic mass | 69.7231 u |
| Series | post-transition metal |
| Group | 13 |
| Period | 4 |
| Block | p-block |
| Phase at STP | Solid |
| Density | 5.904 g/cm³ |
| Melting point | 302.91 K (30 °C) |
| Boiling point | 2673 K (2400 °C) |
| Electronegativity (Pauling) | 1.81 |
| Electron configuration | [Ar] 3d¹⁰ 4s² 4p¹ |
| Crystal structure | Base Orthorhombic |
| Oxidation states | 1,2,3 |
| Discovered | 1875 |
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See Ga in context with all 118 elements.
Working with gallium in a real design?
Ask the materials chat how Ga behaves in your alloy system, what it does to weldability, and which grades to look at — with the source of every number named.