Indium is a metal element with the symbol In and atomic number 49. It is located in Group IIIA of the fifth period of the periodic table. Its simple substance is a silvery white metal with light blue, which is very soft and can be scored with nails. It has strong plasticity, ductility and can be compressed into sheets. Metal indium is mainly used as raw material for manufacturing low melting alloy, bearing alloy, semiconductor, electric light source, etc.