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Gallium (Ga)

QUICK REFERENCE

  • Symbol: Ga
  • Atomic Number: 31
  • Atomic Weight: 69.723
  • Element Classification: Post-transition Metal
  • Discovered By: Lecoq de Boisbaudran
  • Discovery Date: 1875
  • Name Origin: Latin: ‘Gallia’ (France) and perhaps also from the Latin ‘gallus’, meaning rooster, which is a play on the discoverer’s name, Lecoq
  • Density(g/cc): 5.904
  • Melting Point: 29.76°C
  • Boiling Point: 2204°C
  • Appearance: Silvery-blue metal
  • Atomic Radius(pm): 135

Discovery

Gallium was discovered by French chemist Lecoq de Boisbaudran in 1875 through spectroscopic analysis of a sample of sphalerite ore. The discovery was notable because Dmitri Mendeleev had predicted the existence and properties of gallium (which he initially called “eka-aluminum”) in 1871, based on his periodic table. The properties of gallium matched Mendeleev’s predictions so closely that it helped to confirm the accuracy of the periodic table.

Relation to Other Elements

Gallium is a post-transition metal that shares some chemical properties with the group 13 elements, particularly aluminum, which is directly above it in the periodic table. Gallium is unique among metals because it has a low melting point (29.76°C), allowing it to melt in the palm of one’s hand, but it has a very high boiling point. It exhibits both metallic and nonmetallic characteristics, forming gallium(III) compounds similar to those of aluminum and indium, its group neighbors.

Natural Occurrence

Gallium does not occur as a free element in nature but is found as trace amounts in zinc ores and in bauxite. The metal is typically obtained as a byproduct of zinc and aluminum production. Despite its relatively low abundance in the Earth’s crust, gallium plays a critical role in modern electronic devices.

Uses

Gallium’s primary uses are in electronics and semiconductors:

  • Semiconductors: Gallium arsenide (GaAs) and gallium nitride (GaN) are used in semiconductor devices, including diodes, transistors, and integrated circuits. GaAs is particularly valuable in high-speed and high-frequency applications, while GaN is used in LED technology and power electronics.
  • Solar Cells: GaAs is used in high-efficiency solar cells, including those used in space applications where its high efficiency outweighs the cost.
  • Medical Applications: Gallium compounds are used in medical imaging and as a therapeutic agent due to their ability to inhibit bacterial growth and modulate inflammatory responses.
  • Low Melting Alloys: Gallium’s unusual melting point allows it to be used in low melting alloys for high-temperature thermometers and in safety devices that melt at predetermined temperatures.
  • Research and Development: Gallium is used in research laboratories for the synthesis of novel materials and compounds, including superconductors and other advanced materials.

The discovery of gallium was a landmark event that validated the predictive power of the periodic table. Its unique properties and applications, particularly in the field of semiconductors and electronics, have made it an indispensable element in the advancement of modern technology.

 

Zinc (Zn)

Germanium (Ge)