Indium - chemistry.

Indium - chemistry. Indium, symbol In, soft, malleable, silvery white metallic element. The atomic number of indium is 49; the element is in group 13 (or IIIa) of the periodic table (see Periodic Law). Indium was discovered spectroscopically in 1863 by the German chemists Hieronymus Theodor Richter and Ferdinand Reich. The element was named for the prominent indigo line in its spectrum. It ranks 63rd in order of abundance of the elements in Earth's crust. Indium melts at about 157°C (about 315°F), boils at about 2072°C (about 3762°F), and has a specific gravity of 7.3. The atomic weight of indium is 114.82. Indium never occurs as a free metal and is usually found in certain zinc, tungsten, tin, and iron ores. It is used as an alloying agent with nonferrous metals, in bearing alloys, and in nuclear-reactor control rods. Certain indium compounds have unique semiconductor properties. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.