What is Indium?

Mary McMahon
Mary McMahon

Indium is a metallic chemical element classified in the poor metals, in group 13 of the periodic table. The element has a number of uses, particularly in the field of LCD manufacture, which consumes the bulk of that on the market annually. Most consumers interact with it only indirectly, as a component in larger items, and the element tends to be expensive because of its relative rarity.

Indium is listed on the periodic table of elements under its symbol In, and the atomic number 49.
Indium is listed on the periodic table of elements under its symbol In, and the atomic number 49.

In nature, indium is often associated with zinc and silver ores. When isolated, it's silver white and extremely soft, with very high malleability. It is not considered toxic in a purified form, although some compounds may be harmful. Many of these are considered carcinogens, and they will at the very least cause severe organ damage. Indium is listed on the periodic table of elements under its symbol In, and the atomic number 49.

Ferdinand Reich and Hieronymus Theodor Richter are credited with the discovery of indium in 1863. The element appears to have been found while the two were isolating substances found in zinc ores, and it was named for the characteristic rich indigo colored line in its atomic spectrum. Several years after the discovery, Richter succeeded in isolating the element for the first time. Intriguingly, Reich was actually color blind, which is why he worked with Richter, since his partner could make observations that relied on the perception of color.

Many industries use indium in plating for materials like bearings and other moving parts. It is also used to plate silver and in the construction of transistors, especially in the form of solder. The semiconductor industry also uses the element and some of its compounds, and it appears in some medical imaging as well. Indium wire may be used to create seals in an assortment of applications as well. The element resists corrosion extremely well, and many of its uses take advantage of this property.

Since indium is associated with other metal ores, it is usually viewed as a byproduct of the mining industry. In other words, mining companies do not specifically look for this element, they mine other valuable metal ores and view this element as a profitable bonus. Much of the world's supply is produced at mining facilities in Canada; until 1924, it was actually extremely difficult to find in its pure form. As more electronic waste is recycled rather than being thrown away, it has led to less pressure on the world indium market, since usable material can be recovered.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


For a while there, I know they were worried that indium was going to run out. I read an article where the author listed a bunch of things that we didn't even know we rely on, that might soon be exhausted and indium was one of them.

It's not absolutely critical as a mineral, I guess, although I think they use it in solar power cells.

But, the guys who mine it reckon that with recycling and improved mining methods, it isn't actually going to run out any time soon.

Assuming they aren't being overly optimistic, we can hope for the best!


I also learned in my biology class that radioactive indium is used in medical tests. It can be made to show how certain proteins and blood components move around in the body. They take out some blood, "label" it with radioactive indium, then inject it back in to see where it goes.

They make it radioactive so it is easier to detect and follow. Of course, it's only slightly radioactive, and not enough to harm the patient.

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