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Selenium dioxide is the chemical compound with the formula SeO 2. This colorless solid is one of the most frequently encountered compounds of selenium . It is used in making specialized glasses as well as a reagent in organic chemistry.
Industrial production of selenium usually involves the extraction of selenium dioxide from residues obtained during the purification of copper. Common production from the residue then begins by oxidation with sodium carbonate to produce selenium dioxide, which is mixed with water and acidified to form selenous acid (oxidation step).
Selenium forms two oxides: selenium dioxide (SeO 2) and selenium trioxide (SeO 3). Selenium dioxide is formed by the reaction of elemental selenium with oxygen: [5] + It is a polymeric solid that forms monomeric SeO 2 molecules in the gas phase. It dissolves in water to form selenous acid, H 2 SeO 3.
Sodium chloride (table salt, rock salt) ... Chlorine dioxide – ClO 2; ... Selenium dioxide – SeO 2; Selenium disulfide – SeS 2;
Oxidations involving selenium dioxide are often carried out with catalytic amounts of the selenium compound and in presence of a sacrificial catalyst or co-oxidant such as hydrogen peroxide. SeO 2-based oxidations sometimes afford carbonyl compounds such as ketones, [24] β-Pinene [25] and cyclohexanone oxidation to 1,2-cyclohexanedione. [26]
Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method. [4] Instead, selenic acid may also be prepared by the oxidation of selenous acid (H 2 SeO 3) with halogens, such as chlorine or bromine, or with potassium permanganate. [6]
Selenium oxide may refer to either of the following compounds: Selenium dioxide, SeO 2; Selenium trioxide, SeO 3; Diselenium pentoxide, Se 2 O 5
Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. [7] In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. [8]