Selenium, often overlooked, is an element with the atomic number 34 and symbol Se. It’s a non-metal that straddles the line between metals and non-metals in the periodic table, making it quite unique.
Table of Contents
What is Selenium?
Selenium is a semi-conductive element that’s both brittle and shiny in its pure form. It comes in several forms, including red, black, and gray, with the gray form being the most stable. Discovered in 1817 by Jöns Jacob Berzelius, selenium was named after Selene, the Greek goddess of the moon, due to its similarity to tellurium, which was named after the Earth.
Where is Selenium Found?
While selenium isn’t abundant, you can find it in minor amounts in the Earth’s crust, often as a byproduct of copper refining. It’s also present in some soils, which can lead to its uptake by plants, making it an essential nutrient for animals and humans.
Applications of Selenium
- Photocopiers and Solar Cells: Selenium’s photoconductive properties make it ideal for use in photocopiers and solar cells. When light hits selenium, it changes its electrical conductivity, a principle used in early photocopying technology.
- Glass Industry: Selenium is used to decolorize glass, removing green or yellow tints caused by iron impurities. It can also be used to color glass red.
- Electronics: In the manufacture of semiconductors and rectifiers, selenium’s ability to conduct electricity when exposed to light is crucial.
- Nutrition: Selenium is an essential micronutrient for humans and animals. It plays a critical role in antioxidant defense, thyroid function, and immune system health. However, there’s a fine line between beneficial and toxic levels of selenium in the body.
Environmental Impact
Selenium can be toxic in larger amounts, leading to environmental concerns, especially near mining operations where it can leach into water systems. In some areas, this has led to bioaccumulation in aquatic life, affecting wildlife and ecosystems.
Selenium has a unique role in the animal kingdom; some bacteria and certain fungi use selenium in place of sulfur in their enzymes, showcasing the element’s versatility in biological systems.
Conclusion
Selenium might not catch headlines like gold or silver, but its applications are deeply embedded in modern technology, health, and environmental science. From enhancing our gadgets to ensuring our well-being, selenium’s subtle influence is profound. Next time you print a document or enjoy the benefits of a solar-powered device, remember the role of selenium, the unsung hero of elements.
