20 Interesting Facts About Indium
Indium is an element in group 13 of the periodic table of chemical elements, atomic number 49. It is denoted by the symbol In (Latin: Indium). Indium is a non-ferrous metal with a silvery-white color. The inner cut of indium has a bluish tint. When bent, it slightly crunches due to the disruption of the crystals that form when it hardens. It is similar in chemical properties to aluminum and gallium, and in appearance to zinc.
1. Indium was discovered by German chemists Ferdinand Reich and Theodore Richter in 1863 during a spectroscopic study of zinc blende. They searched for thallium, but instead of the green line of this element, they found a bright unknown line of blue color in the spectra (Professor F. Reich suffered from color blindness and could not distinguish the colors of the spectral lines, so all observations were recorded by his assistant Richter). Subsequently, the metal was isolated by Richter in insignificant quantities, but at the World’s Fair of 1867, a half-kilogram ingot of indium was already presented.
2. Indium is a light metal and can be easily cut with a regular knife. It is twenty times softer than gold.
3. If you start bending the indium, it will make a characteristic sound similar to a squeak or crunch. It appears from the deformation of the crystal lattice of the substance.
4. It is the softest metal you can hold in your hands. Only lithium is superior to it, but it is too reactive and immediately oxidizes in the air, forming a poisonous alkali.
5. The melting point is 156.5985 °C (429.7485 K) and the boiling point is 2072 °C (2345 K).
6. Indium burns at +800 °C, the flame is colored blue-violet, or indigo.
7. The alloy of indium and gallium is very fusible and becomes liquid at +16 °C.
8. Even if you stay in the air for a long time, it does not fade. Nor does it happen when the metal is melted.
9. The density of crystalline indium is 7310 kg/m3, and molten indium is 7030 kg/m3.
10. It dissolves in sulfuric and hydrochloric acids, faster in nitric and perchloric acids, reacts slowly with hydrofluoric acid when heated, organic acids (formic, acetic, oxalic, citric) gradually dissolve indium.
11. An alloy with 40% platinum has a golden-yellow color. “Green gold” is an alloy of 75% gold with 20% silver and 5% indium.
12. In nature, it exists in the form of two isotopes: In113 and In115. The latter is more common but is radioactive. What is the period of indium metal 115? It decays in 6 × 1014 years, turning into tin. There are also about 20 artificial isotopes that decay much faster. The longest-lived among them has a half-life of 49 days.
13. Indium metal does not form independent deposits. It is very diffuse and in the form of nuggets is extremely rare. Among the native minerals are indium: sakuranite, rokesite, patrukite, jalindite. However, their rarity does not allow them to be used in industry.
14. The content of indium in the earth’s crust (clark) is 0.25 g/t (it is three times more abundant than silver), in seawater 0.018 mg/l
15. Today, Canada is one of the main producers of indium. In addition, large volumes of metal are mined by the United States, China, Japan, and South Korea. However, the reserves of this element are very limited, it is assumed that they will run out within a few decades.
16. 600-800 tons are mined per year, which absolutely does not cover all the needs for it.
17. The element indium has many useful properties, due to which it is used in astronautics, engineering, electronics, nuclear industry and other industries. Indium tin oxide is used for semiconductors and various solders. In addition, it is used to make computer monitors, TV screens and tablets. In alloy with silver or on its own, it is used for astronomical mirrors and car headlight mirrors.
18. Indium metal improves the wettability and corrosion resistance of the alloy. It is used to cover lead-silver bearings, which are used in aviation and automotive technology. It is also capable of lowering the melting point of other metals. For example, its mixture with tin, lead, cadmium and bismuth melts at 46.5 °C, which is why it is used for fire alarms.
19. Nothing is known about the biological role of this element in our body, but it has been learned to be used in medicine. It is used as a radioactive drug in diagnosing the liver, brain, and lungs to detect tumors and other diseases.
20. The maximum permissible concentration of indium in the air of the working area is 0.1 mg/m3. However, after the information about lung diseases appeared, the rules began to be tightened. For example, the Japanese National Institute for Occupational Safety and Health has set the MPC at 0.0003 mg/m3.