Indium is a chemical element; it has symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for the indigo blue line in its spectrum.
Indium
Indium wetting the glass surface of a test tube
A magnified image of an LCD screen showing RGB pixels. Individual transistors are seen as white dots in the bottom part.
Ductile indium wire
Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised.
Dalton's symbols for the more common elements, as of 1806, and the relative weights he calculated. The symbols for magnesium and calcium ("lime") were replaced by 1808, and that for gold was simplified.