Gallium

Know anything about gallium?
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What else do you need to know, thats not on this site?

Gallium is a chemical element in the periodic table that has the symbol Ga and atomic number 31. A rare, soft silvery metallic poor metal, gallium is brittle at low temperatures but is liquid above room temperature and can indeed melt in the hand. It occurs in trace amounts in bauxite and zinc ores. Gallium arsenide is used as a semiconductor, most notably in light-emitting diodes (LEDs).

Very-pure gallium has a stunning silvery color and its solid metal fractures conchoidally like glass. Gallium metal expands 3.1 percent when it solidifies and therefore should not be stored in either glass or metal containers. Gallium also corrodes most other metals by diffusing into their metal lattice.
Gallium is one of four metals (with caesium, mercury, and rubidium) which are liquid at near normal room temperature and can therefore be used in high-temperature thermometers. It is also notable for having one of the largest liquid ranges for a metal and for having a low vapor pressure at high temperatures.

This metal has a strong tendency to supercool below its melting point thus necessitating seeding in order to solidify. High-purity gallium is attacked slowly by mineral acids. The melting point temperature is very low, T=30 ?C, and the density is higher in the liquid state than in the crystalline state (like in the case of water; the opposite effect is normally found for metals).

Gallium does not crystallize in any of the simple crystal structures. The stable phase under normal conditions is orthorhombic with 8 atoms in the conventional unit cell. Each atom has only one nearest neighbor (at a distance of 2.44 ?) and six other neighbors within additional 0.39 ?. Many stable and metastable phases are found as function of temperature and pressure.

The bonding between the nearest neighbors is found to be of covalent character, hence Ga2 dimers is seen as the fundamental building block of the crystal. The compound, gallium arsenide can convert electricity directly into coherent light (this property is vital to light-emitting diodes).

Analog integrated circuits are the the most common application for gallium, with optoelectronic devices (mostly laser diodes and light-emitting diodes) as the second largest end use.
Other uses include:
Since it wets glass or porcelain, gallium is used to create brilliant mirrors.
Used widely to dope semiconductors and produce solid-state devices like transistors.
Gallium readily alloys with most metals, and has been used as a component in low-melting alloys.
Magnesium gallate containing impurities (such as Mn+2), is beginning to be used in ultraviolet-activated phosphor powder.

Gallium (Latin Gallia meaning "France"; also gallus, meaning "cock") was discovered spectroscopically by Lecoq de Boisbaudran in 1875 by its characteristic spectrum (two violet lines) in an examination of a zinc blende from the Pyrenees. Before its discovery, most of its properties had been predicted and described by Dmitri Mendeleev (who called the hypothetical element eka-aluminum) on the basis of its position in his periodic table. Later in 1875, Boisbaudran obtained the free metal through the electrolysis hydroxide in KOH solution. He named the element after his native land of France and, in one of those multilingual puns so beloved of men of science of the early 19th century, after himself, as 'Lecoq' = the rooster, and Latin for rooster is "gallus".

This true metal is oftentimes found as a trace component in bauxite, coal, diaspore, germanite, and sphalerite. Some flue dusts from burning coal have been shown to contain as much 1.5 percent gallium.

Therefore the element is expensive. It is also used as a high-temp. thermometer as its melting point is 29'C and boiling point is above 1000'C. It has the longest range of liquid range in all metals.

They also use Ga ions in SIMS (Secondary Ion Mass Spectroscopy). Accelerate Ga ions (fairly heavy) at a sample, it blows off "small chunks" which are analyzed for AMU. The unit can also form an image from the reflected Ga ions, though the resolution is fairly poor, but at least can see roughly what spot on the sample you are probing. Fairly new technology, so $$$$$$$

When you're desperate for the research, $$$$$ is not a problem.

Gallium is fun stuff. Though it's a pain when it liquifies cuz it can take a loooooooooooooong time for the stuff to turn back into a solid again. In the meantime, it covers everything in a silvery mirrorlike finish.

Yesterday it was liquid in Hong Kong but today it is solid

[quote="Deryck"]Yesterday it was liquid in Hong Kong but today it is solid[/quote]

Heh. I use my rubidium, cesium, and gallium as a quick little thermometer during the summer months over here. If my cesium is liquid, then it's warm outside. If my gallium is liquid, then it's getting kind of hot and uncomfortable. If my rubidium is liquid, then it's roasting hot and the air conditioning needs to turn on. :lol:

You should have your air con turned on already when your gallium melts.

[quote="Deryck"]You should have your air con turned on already when your gallium melts.[/quote]

True, but I can survive without it. If my rubidium is liquid, then I cannot survive without the AC. :P

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