Chalcogen

Chalcogens
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
pnictogens ←    → halogens
IUPAC group number 16
Name by element oxygen group
Trivial name chalcogens
CAS group number
(US, pattern A-B-A)
 VIA
old IUPAC number
(Europe, pattern A-B)
 VIB
↓ Period
2
Image: Oxygen
Oxygen (O)
8 Other nonmetal
3
Image: Sulfur
Sulfur (S)
16 Other nonmetal
4
Image: 2 allotropes of selenium: black and red. 3 others not shown.
Selenium (Se)
34 Other nonmetal
5
Image: Tellurium in metallic form
Tellurium (Te)
52 Metalloid
6 Polonium (Po)
84 Other metal
7 Livermorium (Lv)
116 Other metal

Legend

primordial element
naturally occurring by radioactive decay
synthetic element

The chalcogens (ore forming) (/ˈkælkədʒənz/ KAL-kə-jənz) are the chemical elements in group 16 of the periodic table.[1] This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv).[2] 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. The word "chalcogen" is derived from a combination of the Greek word khalkos (χαλκός) principally meaning copper (the term was also used for bronze, brass, any metal in the poetic sense, ore and coin),[3] and the Latinized Greek word genēs, meaning born or produced.[4][5]

Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century. Selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. All of the chalcogens have six valence electrons, leaving them two electrons short of a full outer shell. Their most common oxidation states are −2, +2, +4, and +6. They have relatively low atomic radii, especially the lighter ones.[6]

All of the naturally occurring chalcogens have some role in biological functions, either as a nutrient or a toxin. Selenium is an important nutrient (among others as a building block of selenocysteine) but is also commonly toxic.[7] 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.

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. There are numerous organic chalcogen compounds. Not counting oxygen, organic sulfur compounds are generally the most common, followed by organic selenium compounds and organic tellurium compounds. This trend also occurs with chalcogen pnictides and compounds containing chalcogens and carbon group elements.

Oxygen is generally obtained by separation of air into nitrogen and oxygen.[8] Sulfur is extracted from oil and natural gas. Selenium and tellurium are produced as byproducts of copper refining. Polonium is most available in naturally occurring actinide-containing materials. Livermorium has been synthesized in particle accelerators. The primary use of elemental oxygen is in steelmaking.[citation needed] Sulfur is mostly converted into sulfuric acid, which is heavily used in the chemical industry.[7] Selenium's most common application is glassmaking. Tellurium compounds are mostly used in optical disks, electronic devices, and solar cells. Some of polonium's applications are due to its radioactivity.[2]

  1. ^ House, James E.; House, James Evan (2008). Inorganic chemistry. Amsterdam Heidelberg: Elsevier Academic Press. p. 523. ISBN 978-0-12-356786-4.
  2. ^ a b Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. pp. 375–383, 412–415, 475–481, 511–520, 529–533, 582. ISBN 978-0-19-960563-7.
  3. ^ The New Shorter Oxford Dictionary. Oxford University Press. 1993. p. 368. ISBN 978-0-19-861134-9.
  4. ^ "chalcogen". Merriam-Webster. 2013. Retrieved November 25, 2013.
  5. ^ Bouroushian, M. (2010). Electrochemistry of Metal Chalcogenides. Monographs in Electrochemistry. Bibcode:2010emc..book.....B. doi:10.1007/978-3-642-03967-6. ISBN 978-3-642-03967-6.
  6. ^ Cite error: The named reference Jackson2002 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference The Elements was invoked but never defined (see the help page).
  8. ^ "Saiba como é produzido o oxigênio hospitalar". Conselho Federal de Química. February 18, 2021. Archived from the original on June 30, 2022. Retrieved December 23, 2023.