Indium

Indium is an element in the "poor metals" class (beyond the transition metals, before the nonmetals) of the periodic table. It is soft and silvery-white. It is stable in air and water, but dissolves in acids. It has two stable isotopes (actually one, but another one has a half-life of over 10¹⁴ years).

Indium
Properties
Atomic symbol	In
Atomic number	49
Classification	Poor Metals
Atomic mass	114.818 amu
Number of Stable Isotopes	2
Density (grams per cc)	7.310 g/cm^3
Other Information
Date of discovery	1863
Name of discoverer	Ferdinand Reich and Hieronymous Richter
Name origin	From the indigo blue it shows in a spectroscope.
Uses	Used as a coating for high speed bearings, in high-quality mirrors, solar cells, nuclear power regulators, photo cells, thermistors, transistors, and LCD displays. Also employed in low-melting alloys for safety devices.
Obtained from	Found in some zinc ores, but is primarily produced as a by-product of lead and zinc smelting.

Indium was discovered spectroscopically (many 19th century element discoveries were made this way) while searching for thallium in zinc ores.

Indium oxide, mixed with a small amount of tin(II) oxide, has the remarkable and very useful property of being a transparent conductor of electricity. This makes it useful as the front electrode of liquid crystal displays (LCD).