Indium

Atomic Number 49; Atomic Weight 114.82; Density 7.31 g/ccm;
Melting Point 156.61 °C; Boiling Point 2072 °C; Valence +1, +2 or +3.

The name indium is derived from the characteristic indigo-blue line found in its spectrum. Indium was discovered and isolated in 1863 by Reich and Richter in residues of sphalerite from Freiberg which they investigated for thallium. It is found in many zinc minerals from which it is industrially produced. Indium also occurs in lead and copper ores. Indium is a very soft metal, characterized by its low melting point and its high boiling point.

Its applications are for low-melting alloys and soldering materials, for bearing metals and increasingly nowadays for III/V-semiconductors. Indium compounds are used for various applications, the most important being ITO (indium tin oxide), used as transparent and electrically conductive thin film coating in the manufacturing of displays and solar cells.