Indium (49)

Indium is a very soft, silvery-white metal with a brilliant luster. The pure metal gives a high-pitched "scream" when bent. It wets glass, as does gallium. It is useful for making low-melting alloys. An alloy of 24% indium and 76% gallium is liquid at room temperature. Canada produces the majority of the world's supply of indium.

•Name: Indium
•Symbol: In
•Atomic number: 49
•Atomic weight: 114.818 (3)
•Standard state: solid at 298 K
•CAS Registry ID: 7440-74-6
•Group in periodic table: 13
•Period in periodic table: 5
•Block in periodic table: p-block
•Color: silvery lustrous grey
•Classification: Metallic

Historical information

Indium was discovered by Ferdinand Reich, Hieronymus Theodor Richter at 1863 in Germany. Origin of name is from the indigo line in its atomic spectrum. Indium was discovered by Ferdinand Reich and Theodore Richter, who later isolated the metal. It was found and spectroscopically identified as a minor component in zinc ores. Until 1924, a gram or so constituted the world's supply of this element in isolated form. In fact, it is probably about as abundant as silver.

Physical properties

•Melting point: 429.75 [or 156.6 °C (313.88 °F)] K
•Boiling point: 2345 [or 2072 °C (3762 °F)] K
•Density of solid: 7310 kg m-3

Orbital properties

•Ground state electron configuration: [Kr].4d10.5s2.5p1
•Shell structure: 2.8.18.18.3
•Term symbol: 2P1/2

 

Isolation

Indium would not normally be made in the laboratory as it is commercially available. Indium is a byproduct of the formation of lead and zinc. Indium metal is isolated by the electrolysis of indium salts in water. Further processes are required to make very pure indium for electronics purposes.