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Hydrogen selenide is hazardous, being the most toxic selenium compound [3] and far more toxic than its congener hydrogen sulfide. The threshold limit value is 0.05 ppm. The gas acts as an irritant at concentrations higher than 0.3 ppm, which is the main warning sign of exposure; below 1 ppm, this is "insufficient to prevent exposure", while at ...
The parent inorganic selenide is hydrogen selenide (H 2 Se). It is a colorless, malodorous, toxic gas. It dissolves in aqueous solution, to give the hydrogenselenide or biselenide ion HSe −. 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 −
Selenium disulfide has been used in shampoo as an antidandruff agent, an inhibitor in polymer chemistry, a glass dye, and a reducing agent in fireworks. [6] Selenium trioxide may be synthesized by dehydrating selenic acid, H 2 SeO 4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide: [8]
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]
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.
Hydrogen sulfide is a chemical compound with the formula H 2 S.It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. [11]
Selenium disulfide, also known as selenium sulfide, is a chemical compound and medication used to treat seborrheic dermatitis, dandruff, and pityriasis versicolor. [ 1 ] [ 2 ] It is applied to the affected area as a lotion or shampoo. [ 3 ]
Formation of conjugated double bonds is favored. Endocyclic double bonds tend to predominate over exocyclic ones, unless no syn hydrogen is available in the ring. Selenium in these reactions is almost always stereogenic, and the effect of epimerization at selenium (which is acid-catalyzed and occurs readily) on the elimination reaction is ...