The discovery of indium is very similar to that of gallium. German chemists Ferdinand Reich and Hieronymous Theodor Richter in 1863 detected an unfamiliar spectral signature in zinc ore. Richter isolated the new metal four years later and named it after the indigo spectral line.
Indium was primarily a laboratory curiosity until it was used as a lubricant in aircraft engines in World War II. It has also been used in fuses, solders, and other low-melting point metals.
Mining and Production
Indium is not particularly rare. It is found as a trace element in ores of copper, iron, lead, and particularly zinc. It can be isolated by standard refining methods.
World production of indium was about 820 tonnes in 2014, 50% from China and 18% from the Republic of Korea.
Properties and Uses
Indium is a soft, lustrous, silvery metal. It is in many ways similar to gallium, which is above it in the periodic table, and in other ways similar to zinc. A pure indium wire will emit a noise when bent, like pure tin.
Indium is still used somewhat for its historical purposes in solders and lubricants. A new thin-film flexible material for solar power includes indium.
The compound indium tin oxide is a transparent conductor. Thus, it is the substance that makes possible liquid crystal displays (LCDs). LCDs are used in flat-panel televisions, computer monitors, and hand-held devices such as cellphones. Over 80% of the indium produced each year goes into LCDs.