 |
Atomic Number: |
49 |
Melting Point: | 156.6 ºC | |
| Atomic Symbol: | In | Boiling Point: | 184.4 ºC | ||
| Atomic Weight: | 114.82 amu | Density: | 7310
kg/m 3 |
||
| Atomic Radius: |
162.6 pm |
Oxidation States: | 3 | ||
| Covalent Radius: | 144 pm | Electron Configuration: | [Kr]5s24d105p1 | ||
| van der Waals Radius: |
193 pm |
State of Matter: | solid |
(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.
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.
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.
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.
The first large-scale application for indium was as a coating for bearings in high-performance aircraft engines during World War II. Afterwards, production gradually increased as new uses were found in fusible alloys, solders, and electronics. In the middle and late 1980s, the development of indium phosphide semiconductors and indium-tin-oxide thin films for liquid crystal displays (LCD) aroused much interest. By 1992, the thin-film application had become the largest end use.
It has also found application in making low-melting alloys; an alloy of 24% indium - 76% gallium is liquid at room temperature. It is used in making bearing alloys, germanium transistors 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. Its oxide is used in the making of electroluminescent panels.
Twenty-three isotopes of indium are known, however, only one stable isotope, In-127, occurs naturally.
There is evidence that indium has a low order of toxicity; however, care should be taken until further information is available.