Figure 1. Gallium, with atomic number 31 and atomic weight of 69.723.[1]

Gallium is the 31st element on the periodic table of elements.[2] Some of its properties are listed below:[2]

Atomic weight 69.723
Density (at 0oC) 5.91 g/cm3
Boiling point 2502 K
Melting point 302.9146 K

Gallium is a soft, light silver metal. It largely exists as a trace element in minerals and compounds. Gallium is unique in its low melting point (average human body temperature is enough to melt it) but a high boiling point.[2]

Gallium Uses

Figure 2. Gallium sealed in vacuum ampoule.[3]

Gallium arsenide and gallium nitride are used in red and blue/green LED lights, respectively. Both compounds are also used in semiconductors. Gallium arsenide has a molecular structure similar to silicon and can act as a substitute, particularly in electronics, and was used in the solar panels for the Mars Rover. Gallium nitride is also used Blu-ray technology, mobile phones, and pressure sensors for touch switches.[2]

Gallium will alloy with most metals and is often used in low-melting point alloys due to its own low melting point. Gallium's high boiling point makes it useful for recording high temperatures that would normal destroy a regular thermometer, since it takes very high temperatures for gallium to reach the point of vapourisation. It is sometimes used as non-toxic substitute for mercury in regular thermometers.[4]


Gallium has two isotopes found in nature:[2]

Symbol Natural Abundance
69Ga 60.108%
71Ga 39.892%


The video below is from the University of Nottingham's periodic videos project.[5] They have created a complete suite of short videos on every element on the periodic table of elements.

For Further Reading


  1. Made internally by a member of the Energy Education team.
  2. 2.0 2.1 2.2 2.3 2.4 Royal Society of Chemistry Periodic Table, Gallium [Online], Available:
  3. Wikimedia Commons, File:6N Gallium sealed in vacuum ampoule.jpg [Online], Available:
  4. John Emsley, "Nature’s Building Blocks: An A-Z Guide to the Elements", Oxford University Press, New York, 2nd Edition, 2011.
  5. See more videos from the University of Nottingham on different elements here: