Selenium and tellurium are chemical elements in the p-block of the periodic table. Tellurium is a metalloid and selenium is also sometimes considered as a metalloid, but it is actually a non-metal. Both these are in the solid-state at room temperature.
What is Selenium?
Selenium is a chemical element having the atomic number 34 and chemical symbol Se. It is a non-metal which is in the p-block of the periodic table. There are different allotropic forms of selenium, such as black, red, and gray selenium. We can find this material either as the pure element or as a component in its ore on the Earth’s crust. E.g. metal sulfide ores.
Moreover, Selenium has several allotropic forms which interconvert upon temperature changes. Among these allotropes, gray selenium is the most stable and dense form. If we prepare this material in a laboratory, we get an amorphous powder which appears in brick red color. When considering the isotopes of selenium, it has seven stable isotopes that occur naturally. The selenium-80 isotope has the highest abundance among them. Apart from that, there are some radioactive isotopic forms of selenium, as well.
Concerning the applications, selenium is important in manganese electrolysis to decrease the power required to operate the electrolytic cells. Also, one of the largest applications of selenium is in glass production; it gives a red color to the glass. It is also useful in producing alloys in order to replace toxic alloying components such as lead. Moreover, selenium is important in producing solar cells as a component in copper indium gallium selenide. However, the salts of selenium are toxic. Nevertheless, trace amounts of selenium are required for cellular function in organisms such as animals.
What is Tellurium?
Tellurium is a chemical element having the atomic number 52 and chemical symbol Te. It is a metalloid which appears in a silver-white color. Also, this material is brittle, mildly toxic, and is rare in nature as well. Besides, it has two allotropic forms; the crystalline form and the amorphous form. Considering its isotopes, tellurium has eight isotopes that are naturally occurring. Among these isotopes, six are very stable while the other two are radioactive. But, they are only slightly radioactive because they have long half-lives. There are about 31 artificial radioactive isotopes of tellurium as well.
Furthermore, tellurium is a semiconductor material. Depending on the atomic arrangement, it shows greater conductivity in some directions. Moreover, the conductivity increases upon exposure to light. However, unlike selenium, tellurium has no biological function.
When considering the applications of tellurium, it is important as an alloying element, as a semiconductor, as pigments for ceramics, as an oxidizer, producing iodine-131, etc.
What is the Difference Between Selenium and Tellurium?
Selenium and tellurium are chemical elements which are located adjacent to each other in the same group in the periodic table, group 16. The key difference between selenium and tellurium is that selenium is a non-metal, whereas tellurium is a metalloid.
Moreover, selenium is required in trace amounts for biological function in cells of most animals, but tellurium has no biological function. When considering the applications of tellurium, it is important as an alloying element, as a semiconductor, as pigments for ceramics, as an oxidizer, producing iodine-131, etc.
Below is a summary of the difference between selenium and tellurium.
Summary – Selenium vs Tellurium
Selenium and tellurium are chemical elements which are located adjacent to each other in the same group in the periodic table, group 16. The key difference between selenium and tellurium is that selenium is a non-metal whereas tellurium is a metalloid.
1. Helmenstine, Anne Marie. “Tellurium Facts.” ThoughtCo, Oct. 7, 2019, Available here.