Indium is classed as an ‘other’ metal. Like Gallium it exists in a state of a liquid over a wide range of temperatures due to its low melting point and high boiling point. It is used in the production of gallium alloys with low melting points and also used in the production of semiconductors. Indium is found in zinc minerals in the earths crust. It was discovered in 1863 by Ferdinand Reich upon examining zinc sulfide ores he isolated Indium. After careful spectrum analysis he discovered a bright indigo line. It is located in Group 13 as a metal. It has a melting point of 156°c and a boiling point of 2070°c.
Ferdinand Reich, T. Richter