Appearance and Characteristics
Harmful effects:
Indium is considered to be of low toxicity.
Characteristics:
Indium is a very soft, silvery-white lustrous metal. Indium liquid clings to or wets glass and similar surfaces. Like gallium, indium remains in a liquid state over a wide range of temperatures. When present in compounds, indium exists mostly in the oxidation state III. When heated above its melting point, it burns with a violet flame to the yellow sesquioxide (In2O3).
Uses of Indium
Indium is used in the production of low-melting alloys, typically with gallium. The melting point depends on the ratio of indium to gallium. An alloy with 24% indium and 76% gallium, for example, melts at just 16 oC. This type of alloy can be used as a non-toxic alternative to mercury in some applications. Compounds of indium are used in the semiconductor industry for germanium transistors, thermistors, rectifiers and photocells. Indium can be coated on metals and evaporated onto glass, to form mirrors equal to that made with silver but more corrosion resistant. Indium-tin oxide thin films are used for liquid crystal displays (LCDs).