Some of polonium's applications are due to its radioactivity. Tellurium compounds are mostly used in optical disks, electronic devices, and solar cells. Selenium's most common application is glassmaking. Sulfur is mostly converted into sulfuric acid, which is heavily used in the chemical industry. The primary use of elemental oxygen is in steelmaking. Livermorium has been synthesized in particle accelerators. Polonium is most available in naturally occurring actinide-containing materials. Selenium and tellurium are produced as byproducts of copper refining. Sulfur is extracted from oil and natural gas. Oxygen is generally obtained by separation of air into nitrogen and oxygen. This trend also occurs with chalcogen pnictides and compounds containing chalcogens and carbon group elements. Not counting oxygen, organic sulfur compounds are generally the most common, followed by organic selenium compounds and organic tellurium compounds. There are numerous organic chalcogen compounds. Sulfur has more than 20 allotropes, oxygen has nine, selenium has at least eight, polonium has two, and only one crystal structure of tellurium has so far been discovered. Tellurium often has unpleasant effects (although some organisms can use it), and polonium (especially the isotope polonium-210) is always harmful as a result of its radioactivity. Selenium is an important nutrient (among others as a building block of selenocysteine) but is also commonly toxic. Īll of the naturally occurring chalcogens have some role in biological functions, either as a nutrient or a toxin. They have relatively low atomic radii, especially the lighter ones. Their most common oxidation states are −2, +2, +4, and +6. All of the chalcogens have six valence electrons, leaving them two electrons short of a full outer shell. Selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century. The word "chalcogen" is derived from a combination of the Greek word khalkόs ( χαλκός) principally meaning copper (the term was also used for bronze/ brass, any metal in the poetic sense, ore or coin), and the Latinized Greek word genēs, meaning born or produced. Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). This group is also known as the oxygen family. Reacts on heating to form a black solid.The chalcogens (ore forming) ( / ˈ k æ l k ə dʒ ə n z/ KAL-kə-jənz) are the chemical elements in group 16 of the periodic table. Reacts as a powder on very strong heating. Reacts readily when heated as iron filings. Yellow solid forms which changes to white on cooling. Reacts steadily when heated forming a yellow solid which changes to white on cooling. Reacts readily with strong heating as a powder. Slowly forms a surface oxide at room temperature Yellow/orange flame and white solid formed. Tarnishes when freshly cut at room temperature
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