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Indium

Author: Robert Husted, Mollie Boorman

Atomic Number 49
Atomic Symbol In
CAS ID No. 7440-74-6
Atomic Weight 114.8200 amu
Electron Configuration [Kr] 4d10 5s2 5p1
Melting Point 156.8 C
Boiling Point 2073 C
Density 7.310 g/cm3
History

(from the brilliant indigo line in its spectrum) Discovered by Reich and Richter, who later isolated the metal. Until 1924, a gram or so constituted the world's supply of this element in isolated form. It is probably about as abundant as silver. About 4 million troy ounces of indium are now produced annually in the Free World. Canada is presently producing more than 1,000,000 troy ounces annually.

Sources

Indium is most frequently associated with zinc materials, and it is from these that most commercial indium is now obtained; however, it is also found in iron, lead, and copper ores.

Properties

Indium is available in ultra pure form. Indium is a very soft, silvery-white metal with a brilliant luster. The pure metal gives a high-pitched "cry" when bent. It wets glass, as does gallium.

Uses

It has found application in making low-melting allows; an allow of 24% indium - 76% gallium is liquid at room temperature. It is used in making bearing alloys, germanium transistors, rectifiers, thermistors, and photoconductors. It can be plated onto metal and evaporated onto glass, forming a mirror as good as that made with silver but with more resistance to atmospheric corrosion.

Handling

There is evidence that indium has a low order of toxicity; however, care should be taken until further information is available.




Last Update: 2011-02-16