Terbium

Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white rare earth metal that can be bent and stretched. Terbium belongs to a group of elements called the lanthanides.

Swedish chemist Carl Gustaf Mosander discovered terbium in 1843. He found it inside a compound called yttrium oxide.

Terbium has many useful applications. It is added to materials to improve them in devices and helps keep fuel cells stable. When mixed with other elements to form an alloy called Terfenol-D, terbium helps create materials that change size in response to magnetic fields. This makes it valuable for use in devices like actuators, naval sonar systems, and sensors.

One of the biggest uses of terbium is in green phosphors, materials that glow in the dark. Terbium oxide is used in fluorescent lamps and in the screens of old television and computer monitors. It helps create bright, efficient white light used in indoor lighting.

Characteristics

Terbium is a shiny, silvery-white metal that is soft and easy to shape. It is part of a group called rare earth elements. This metal stays stable in air and has a special way its atoms are arranged.

Terbium glows brightly in yellow and green colors, which makes it useful for some lighting. It can react with water and many other substances, so it changes when it meets them. Scientists often study terbium in labs because of these interesting properties.

History

A Swedish chemist named Carl Gustaf Mosander discovered terbium in 1843. He found it mixed with a material called yttrium oxide. Terbium and some other elements are named after a village in Sweden called Ytterby. It took many years and new science methods before scientists could fully separate and study terbium.

Early scientists had a hard time telling terbium apart from another element called erbium. They used different chemicals to try to separate them, but it was difficult. Later, they had better tools to study these elements.

Occurrence

Terbium is found with other rare earth elements in minerals such as monazite and xenotime. It is not very common in the Earth's crust.

Scientists have also found terbium in the atmosphere of a planet called KELT-9b, far outside our Solar System.

The largest amounts of terbium used come from special clays in southern China. Smaller amounts are found in minerals like bastnäsite and monazite. In 2018, a large supply of terbium was found near Japan's Minamitori Island.

Production

To get terbium, minerals that contain it are crushed and treated with hot, strong sulfuric acid. This makes compounds that can dissolve in water. The solution is then treated with ammonium oxalate to form solid compounds. These solids are heated to create oxides.

The oxides are dissolved in nitric acid, leaving behind one of the main components, cerium.

The best way to separate terbium from other rare earth elements is using ion exchange. In this process, the elements stick to a special material and are later washed off with certain chemicals. Finally, terbium metal is made by using heat and chemicals to remove impurities.

There are large amounts of rare earth minerals available around the world.

Applications

Terbium helps improve certain materials, like calcium fluoride, calcium tungstate, and strontium molybdate. These materials make solid-state devices work better. Terbium also helps keep fuel cells stable when they get very hot.

Terbium is used in special mixtures called alloys to make electronic devices. One important mixture, called Terfenol-D, changes size when a magnetic field is nearby. This is useful in naval sonar, sensors, and other devices. Terbium can also make certain lights glow brightly, which is useful in old-style TV screens and energy-saving lights. In 2023, scientists used terbium to study a single iron atom in detail.

Safety

Terbium, like many rare earth elements, is not well studied for its effects on health and the environment. There are not many rules about safe levels of exposure to terbium.

Some research shows that terbium can build up in the environment and may harm fish and plants. Very high amounts of terbium might make other harmful substances more dangerous to plant cells.