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Selenium compounds are compounds containing the element selenium (Se). Among these compounds, selenium has various oxidation states, the most common ones being −2, +4, and +6. Selenium compounds exist in nature in the form of various minerals, such as clausthalite, guanajuatite, tiemannite, crookesite etc., and can also coexist with sulfide ...
At higher pH, selenide forms. Solutions of hydrogen selenide and selenide are oxidized by air to give elemental selenium: 2 SeH − + O 2 → 2 Se + 2 OH −. Most elements form selenides. They sometimes have salt-like properties, e.g. sodium selenide, but most exhibit covalent bonding, e.g. molybdenum diselenide. Their properties are diverse ...
Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon-to-selenium chemical bonds. [ 1 ] [ 2 ] [ 3 ] Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected.
It is the oxyanion of selenium. It is the selenium analog of the sulfite ion, SO 2− 3. Thus selenite is pyramidal and selenium is assigned oxidation state +4. Selenite also refers to compounds that contains this ion, for example sodium selenite Na 2 SeO 3 which is a common source of selenite. [1]
Selenium hexafluoride is the inorganic compound with the formula SeF 6. It is a very toxic colourless gas described as having a "repulsive" odor. [ 5 ] It is not widely encountered and has no commercial applications.
The original synthesis involved the redistribution reaction of selenium dioxide and selenium tetrachloride. Pure selenium oxydichloride autoionizes to a dimer: [4] SeOCl 2 ↔ (SeO) 2 Cl + 3 + Cl −. The SeOCl 2 is generally a labile Lewis acid and solutions of sulfur trioxide in SeOCl 2 likely form [SeOCl] + [SO 3 Cl] − the same way. [5]
Selenium is most commonly found as an impurity, replacing a small part of the sulfur in sulfide ores of many metals. [55] [56] In living systems, selenium is found in the amino acids selenomethionine, selenocysteine, and methylselenocysteine. In these compounds, selenium plays a role analogous to that of sulfur.
Hypervalent iodine compounds are useful reagents in organic chemistry (e.g. Dess–Martin periodinane) Tetra-, penta- and hexavalent phosphorus, silicon, and sulfur compounds (e.g. PCl 5, PF 5, SF 6, sulfuranes and persulfuranes) Noble gas compounds (ex. xenon tetrafluoride, XeF 4) Halogen polyfluorides (ex. chlorine pentafluoride, ClF 5)