Properties

Indium is a metal in the Aluminum family, or group 13. Indium has a silvery white color, and a brilliant luster. Its density is approximately 7.31 grams per cubic centimeter. Indium is one of the softest metals, softer than lead. It even makes a mark on paper like a lead pencil does. Even though it does dissolve in acids, there is no reaction between oxygen and indium at room temperature. Although at higher temperatures, they combine to form indium oxide. Indium has just 3 valence electrons. Having this odd number of valence electrons, it is hard for indium to bond with other elements, and it’s electronegativity proves it, at just 1.78. To give you an example of a high electronegativity, fluorine, which is an element that is quite easy to bond with, is 3.98. Indium is solid at room temperature, and when it’s bent, it makes a loud screech, or “tin cry”.

History

Indium was first discovered in 1863, by two German chemists named Ferdinand Reich and Heironymus Theodor Richter. You may believe that Indium was named after the country India, or Indians, but no. Indium is named after the color indigo, which is a bright type of blue. It gets its name from the indigo blue line it gets in its spectrum. It has never been produced in the US, but it is imported from Canada, China, and Russia. In 1996, just over 45 tons of indium were used in the US.

Malleability

Out of all of its many properties, its malleability is probably the most important. If indium wasn’t malleable, then there wouldn’t be much use for it. Because of indium’s incredible malleability, it is often used to make soft wires, sometimes used to go into hard-drives. Indium also has an extremely low melting point, so it is even more malleable at higher temperatures. Indium is often compared to gallium and tin. Both are very malleable, and are metals, just like indium.

Practical Uses

As proof of indium’s vital use, here’s a fact: just over 45 tons of indium were used in the USA in 1996. When indium is in it’s pure state, it sticks tightly to other metals, including itself. This makes it very useful to bond things together, especially metals. Indium is used almost as a metal glue. In hard-drives, it’s not only used for wiring; indium is also very useful to bond the hard-drive into the computer, without using glue. Some other uses of indium are making alloys, wetting glass to make a mirror (just as good as silver, if I might add), transistors, and photocells. Indium is also used in special equipment that is needed for extremely low temperatures. At just $1-5 per gram, indium is the ideal bonder and wirer.

Where It's Found

Indium is found mainly in zinc ores. It’s abundance in the earth’s crust is about .1 part per million, making it slightly more abundant than silver or mercury. Although indium is primarily found in zinc refineries, it has been discovered while mining in iron, lead, and copper ores.

Toxicity

While indium poisoning has not, and probably never will be, an issue, it can still kill you. From studies, it has shown that if indium is eaten, everything is okay. It just goes right through your digestive track, and, well, you know what happens. On the other hand, if indium is injected into the bloodstream, it can be extremely poisonous, and sometimes fatal.