Terbium is a rare earth element and it belongs to the lanthanide series of the periodic table. It is positioned in the f-block and 6th period. Chemically, it is represented with the symbol Tb. The credit for discovering this chemical element goes to famous Swedish chemist Carl Gustaf Mosander who discovered it in the year 1843. It cannot be found in the form of a free element in nature. The term rare earth element does not mean that terbium is rarely found in the earth but it was quite difficult to purify this metallic element. It is found in many minerals like monazite, gadolinite, xenotime, cerite and so on.
Facts About Terbium
In chemistry, the element terbium show some unique physical and chemical properties. A few such facts are given below:
- The most effective method used for separation of terbium metal or salt from its minerals is ion exchange.
- Terbium is identified by its silvery-white color.
- It is a very soft substance and can be cut with the help of a knife very easily.
- It has good malleable and ductile properties. Hence, it can be shaped, bent and drawn out very easily.
- The atomic number of terbium is 65 and its atomic weight is 158.9254.
- Like any other metal, it is electropositive in nature which means, it loses its electrons present in the outermost shells to form cations.
- The most commonly found valence state of terbium is +3 but sometimes, it can also be found in +4 valence state.
- Terbium can be easily burned in presence of air. On burning, it produces terbium oxide.
- On reaction with water, it forms terbium hydroxide. If the water is cold, then the rate of reaction is going to be quite slow. On the other hand, the reaction with hot water takes place very quickly.
- The terbium (+3) ion exhibits excellent fluorescent property. It emits a brilliant light which is lemon-yellow in color.
- When it reacts with dilute sulfuric acid, it forms a solution which is light pink in color and it gives out hydrogen.
- At high temperature, it combines with a large number of elements to form binary compounds. These elements include nitrogen, sulfur, phosphorus, boron, selenium, silicon, arsenic and so on.
- There is only one stable isotope of terbium and there are 33 radioisotopes of terbium. Most of these isotopes are highly unstable in nature. The most stable radioisotope of terbium is the one with a half life of 180 years.
Uses of Terbium
For all these unique properties of terbium, this chemical element has a wide range of practical application as well. Some important uses are as follows:
- Terbium is used as a component in manufacturing of alloys of various metals.
- Terbium is used on a large scale in phosphors which is used in TV tubes. The phosphor gives out different colors of light when it is stuck by electrons. Phosphor with terbium content gives off a green colored light. It is also used in x-ray screens and fluorescent lamps.
- Terbium is used as a doping agent in a number of substances such as calcium tungstate, calcium fluoride and strontium molybdate. These materials are used in various electronic devices and terbium is added to them as a trace impurity in order to change their electrical and optical properties.
- Another application of terbium is in the making of fuel cells. The best part of terbium fuel cells is that it can function at a very high temperature.
Hope you enjoyed reading about all these terbium facts. Like any other element of lanthanide series, terbium is believed to have a low to medium level of toxicity. For this reason, it is advisable to handle it with extra care.