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Terbium

physical science Maturity 7-9 Next article →

Terbium is a special kind of metal called a rare earth metal. It has a silvery-white color and is quite soft. You can even cut it with a knife!

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

It is known as a malleable and ductile metal. This means it can be shaped or stretched without breaking. Terbium is the ninth member of a group called the lanthanide series. It is a very electropositive metal. This means it reacts easily with things like water. When terbium touches water, it creates hydrogen gas.

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

Finding pure terbium in nature is a hard job. You will never find it as a single, free element. Instead, it hides inside many different minerals. Some of these minerals are called cerite, gadolinite, and monazite. It is also found in xenotime and euxenite.

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

In the crust of the Earth, there is about 1.2 mg/kg of it. Most of the world's supply comes from ion-adsorption clays in southern China. Some people even found a huge supply near Minamitori Island in Japan. This supply might last for 420 years!

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

A Swedish chemist named Carl Gustaf Mosander discovered terbium in 1843.

Mosander Carl Gustav bw
Mosander Carl Gustav bw

He found it while looking at yttrium oxide. He saw it was an impurity in that substance. Terbium, yttrium, and erbium all share a name. They are named after a small village called Ytterby in Sweden.

Mosander Carl Gustav bw
Mosander Carl Gustav bw

It was hard to get terbium in a pure form at first. Scientists had to wait for new ion exchange techniques to help. In the past, people even mixed up the names for erbium and terbium. Scientists used spectral analysis to help fix these mistakes.

Terbium is very useful for making bright light. Most of the terbium in the world is used for green phosphors. A phosphor is a substance that glows when it gets energy.

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

Terbium oxide is used in fluorescent lamps. It is also used in old cathode-ray tubes for televisions and monitors. It works with blue and red phosphors to make white light. This is called trichromatic lighting technology. It helps create high-efficiency light for our homes.

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

This metal also helps with many high-tech machines. It is part of a special mix called Terfenol-D. This alloy expands and contracts when it touches magnetic fields. Because of this, it is used in sensors and naval sonar systems. Terbium also helps fuel cells work at high temperatures. It acts as a crystal stabilizer to keep them steady.

Xenotim mineralogisches museum bonn
Xenotim mineralogisches museum bonn

Even in space, terbium is interesting. Scientists have detected it in the atmosphere of a planet called KELT-9b. This planet is a hot-Jupiter located outside our Solar System.

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File:Mosander Carl Gustav bw.jpg
Mosander Carl Gustav bw.jpg
File:Xenotim mineralogisches museum bonn.jpg
Xenotim mineralogisches museum bonn.jpg
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