Indium was discovered in 1863. It is a rare metal found as a trace element in zinc and lead sulfide ores. Therefore, zinc refineries are the world's major source of indium. Over a thousand kilograms of indium are recovered each year from the flue dust of zinc refineries.

Indium is characterized as a soft and malleable, silvery-white metal. It looks like aluminum, but resembles more like tin when being bent. Indium is soft that it rubs onto other objects in much the same way as graphite and pencil lead. Pure indium can be polished and it will retain its shine as it is corrosion resistant.

Indium is used mostly for electroplating steel bearings. It is used in sprinklers as an alloy as it lowers the melting point of other metals. This low melting point contributes to its commercial value as an alloying agent for soldering material. Relatively small amounts are used in dental items and in semiconductors with phosphorus. Long-lived indium battery has also been devised to power electronic wrist watches.

BCIT Chemistry Resource Center