Selenium is a chemical element; it has symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium (from ) was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth).
Selenium is a chemical element (symbol Se, atomic number 34) that can appear in several different forms, such as a brick-red powder or a grey metallic-looking solid, though it rarely occurs in pure form in nature. It was discovered in 1817 and was named after the Greek word for the moon, chosen because of its similarity to the previously discovered element tellurium, which had been named after the Earth.
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Selenium is a chemical element; it has symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium (from ) was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth).
Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been mostly replaced with silicon semiconductor devices. Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).