Indium

History

(from the brilliant indigo line in its spectrum) Discovered by Reich and Richter, who later isolated the metal. Until 1924, a gram or so constituted the world's supply of this element in isolated form. It is probably about as abundant as silver. About 4 million troy ounces of indium are now produced annually in the Free World. Canada is presently producing more than 1,000,000 troy ounces annually.[1]

Sources

Indium is most frequently associated with zinc materials, and it is from these that most commercial indium is now obtained; however, it is also found in iron, lead, and copper ores.[1]

Properties

General
Name : indium
Symbol : In
Atomic Number : 49
Chemical Series : Post-transition Metal (Poor Metal)
Block, Period : 13, 5
Appearance : silvery lustrous gray
Atomic Properties
Atomic Weight (amu) : 114.818
Covalent Radius (pm) : 144
Physical Properties
Matter : solid (diamagnetic)
Density (kg/) : 7310
Hardness : 1.2
Melting Point (K) : 429.7485
Boiling Point (K) : 2345
Evaporation Heat (kJ/mol) : 231.5
Fusion Heat (kJ/mol) : 2.263
Specific Heat (J/(kg*K) ) : 233
Miscellaneous
Electrical Conductivity (/m ohm) : 11.6
Thermal Conductivity (W/(m*K) ) : 81.8

Indium is available in ultra pure form. Indium is a very soft, silvery-white metal with a brilliant luster. The pure metal gives a high-pitched "cry" when bent. It wets glass, as does gallium.[1]

Uses

It has found application in making low-melting allows; an allow of 24% indium - 76% gallium is liquid at room temperature. It is used in making bearing alloys, germanium transistors, rectifiers, thermistors, and photoconductors. It can be plated onto metal and evaporated onto glass, forming a mirror as good as that made with silver but with more resistance to atmospheric corrosion.[1]

Handling

There is evidence that indium has a low order of toxicity; however, care should be taken until further information is available.[1]

Notes

[1] From Los Alamos National Laboratory's Chemistry Division Website