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It's Elemental

The Element Indium

[Click for Isotope Data]


49 In Indium 114.818

Atomic Number: 49

Atomic Weight: 114.818

Melting Point: 429.75 K (156.60°C or 313.88°F)

Boiling Point: 2345 K (2072°C or 3762°F)

Density: 7.31 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 5

Group Number: 13

Group Name: none

What's in a name? Named after the bright indigo line in its spectrum.

Say what? Indium is pronounced as IN-dee-em.

History and Uses:

Indium was discovered by the German chemists Ferdinand Reich and Hieronymus Theodor Richter in 1863. Reich and Richter had been looking for traces of the element thallium in samples of zinc ores. A brilliant indigo line in the sample's spectrum revealed the existence of indium. Indium is about as abundant as silver but is much easier to recover since it typically occurs along with zinc, iron, lead and copper ores.

Indium is used to coat the bearings of high speed motors since it allows for the even distribution of lubricating oil. Indium is used to dope germanium to make transistors. It is also used to make other electrical components such as rectifiers, thermistors and photoconductors. Indium can be used to make mirrors that are as reflective as silver mirrors but do not tarnish as quickly. Indium is also used to make low melting alloys. An alloy of 24% indium and 76% gallium is a liquid at room temperature.

Estimated Crustal Abundance: 2.5×10-1 milligrams per kilogram

Estimated Oceanic Abundance: 2×10-2 milligrams per liter

Number of Stable Isotopes: 1 (View all isotope data)

Ionization Energy: 5.786 eV

Oxidation States: +3

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d10

5s2   5p1

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