Ga
69.723Gallium
Galyum
Gallium is a soft post-transition metal with atomic number 31. It melts near room temperature, forms important semiconductors such as gallium arsenide and gallium nitride, and was one of Mendeleev’s predicted elements.
31
69.723 g/mol
[Ar] 3d¹⁰ 4s² 4p¹
2 | 8 | 18 | 3
1.81
5.907 g/cm³
29.76 °C
2203.8 °C
Lecoq de Boisbaudran
Gallium was discovered in 1875 by Paul-Émile Lecoq de Boisbaudran using spectroscopy. It closely matched Mendeleev’s predicted eka-aluminum, including density, atomic mass and oxide behavior.
Gallium-69
Natural abundance: About 60.1%. The more abundant stable isotope of gallium.Gallium-71
Natural abundance: About 39.9%. Stable isotope of gallium.GaAs
Gallium ArsenideIII-V semiconductor used in RF electronics, laser diodes, LEDs and high-efficiency solar cells.GaN
Gallium NitrideWide-bandgap semiconductor used in blue LEDs, white LEDs, lasers and power electronics.Ga₂O₃
Gallium(III) OxideUltra-wide-bandgap semiconductor studied for high-power and UV devices.GaCl₃
Gallium(III) ChlorideLewis acid reagent and precursor in gallium chemistry.- Gallium arsenide semiconductors for high-speed electronics, LEDs and solar cells
- Gallium nitride for blue and white LEDs, laser diodes and power electronics
- Low-melting alloys such as gallium-indium-tin mixtures
- Gallium compounds in nuclear medicine and imaging research
- Thermal interface materials and liquid-metal cooling research
Gallium has no known essential biological role. Ga³⁺ can mimic Fe³⁺ in some biological systems, which is why gallium compounds have been studied in medical and antimicrobial contexts.
- Gallium melts at about 29.8 °C, so it can melt in a warm hand.
- Gallium nitride blue LEDs helped make efficient white LED lighting possible.
- Liquid gallium can weaken aluminum by penetrating its grain boundaries.
- Gallium was a major success for Mendeleev’s periodic table predictions.
- Gallium has atomic number 31 and belongs to group 13.
- Its electron configuration is [Ar] 3d¹⁰ 4s² 4p¹.
- Gallium commonly forms Ga³⁺ and many gallium compounds show +3 oxidation state chemistry.
- Gallium sits after the 3d transition series, so its chemistry is influenced by the filled 3d¹⁰ subshell.
What is the atomic number of gallium?
The atomic number of gallium is 31.
What is the electron configuration of gallium?
Gallium has the electron configuration [Ar] 3d¹⁰ 4s² 4p¹.
Why does gallium melt in your hand?
Gallium melts near 29.8 °C, which is below normal body temperature, so a warm hand can melt it slowly.
What is gallium used for?
Gallium is used in semiconductors such as GaAs and GaN, LEDs, laser diodes, solar cells, low-melting alloys and research materials.
What is gallium nitride used for?
Gallium nitride is used in blue and white LEDs, laser diodes, high-power electronics and radio-frequency devices.
Why was gallium important for Mendeleev’s periodic table?
Gallium matched Mendeleev’s predicted eka-aluminum, confirming that the periodic table could predict undiscovered elements.