2.2. Measurement Methods NIOSH S190 (II-7) , 7300 , 7301 , 7303 , 9102 ; [42][43] Ocean water contains significant amounts of selenium. Uses advised against Food, drug, pesticide or biocidal product use. The chief commercial uses for selenium today are glassmaking and pigments. [20] A diet rich in selenium may help keep your heart healthy, as low selenium levels have been linked to an increased risk of heart disease.. Parameters In general. [134], In the regions (e.g. Selenium is a non-metal element with atomic number 34 and an atomic mass of 78.96 (Lide 2000). Usually parameters reproduce the value, and the template adds the SI unit or additional standard text. Deiodinases are able to extract electrons from iodides, and iodides from iodothyronines. Consistent with trends indicated by the double bond rule, selenoketones, R(C=Se)R, and selenaldehydes, R(C=Se)H, are rarely observed. Cancer patients receiving daily oral doses of selenothionine may achieve very high plasma and urine selenium concentrations. NACRES NA.22 It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. [55], Researchers found that application of selenium fertilizer to lettuce crops decreased the accumulation of lead and cadmium. It is recommended that a water concentration of 2 μg Se/L be considered highly hazardous to sensitive fish and aquatic birds. National Research Council, Committee on Nutrient Requirements of Small Ruminants (2007). Inhaled selenium hexafluoride is a highly toxic, corrosive, and irritating gas. [114] In China, people who ingested corn grown in extremely selenium-rich stony coal (carbonaceous shale) have suffered from selenium toxicity. The temperature dependences of the saturated vapor pressure of selenium (700–1100 K) and indium sesquiselenide In 0.4 Se 0.6 (1123–1373 K) are investigated using the gravimetric method. Selenium disulfide is a bright orange colored powder. Selenium occurs naturally in a number of inorganic forms, including selenide, selenate, and selenite, but these minerals are rare. [46][47], Anthropogenic sources of selenium include coal burning, and the mining and smelting of sulfide ores. Selenium's semiconductor properties found numerous other applications in electronics. Substantial physiological changes may occur in fish with high tissue concentrations of selenium. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. 3. Copper indium gallium selenide is a material used in solar cells. In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light. [25] Both chemists owned a chemistry plant near Gripsholm, Sweden, producing sulfuric acid by the lead chamber process. : AC318140000; AC318140250; AC318141000 CAS-No 7488-56-4 Synonyms Selenium disulfide Recommended Use Laboratory chemicals. [6] The structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring. In low doses, selenium has shown a beneficial effect on plant resistance to various environmental stress factors including drought, UV-B, soil salinity, and cold or hot temperatures. [83] It has also been suggested that season could have an impact on the harmful effects of selenium on fish. During the 1980s, selenocysteine was shown to be encoded by the codon UGA. Selenium was later confirmed to be the toxic factor. Calcium carbide and selenium vapor react with incandescence [Mellor 5:862 1946-47]. With strong reducing agents, it forms polyselenides. To the knowledge of researchers, there are no reports of mercury levels exceeding that of selenium levels in ocean fish. Illustrative selenides include mercury selenide (HgSe), lead selenide (PbSe), zinc selenide (ZnSe), and copper indium gallium diselenide (Cu(Ga,In)Se2). Based on the these experimental results, P-T-x equilibrium relations of Bi-Se alloys were determined. Deviations from stoichiometry and electrical properties in SnTe. Light sensitivity makes a-Se a unique system to study the role of surface structure and dynamics on stable … The glutathione peroxidase family of enzymes (GSH-Px) catalyze certain reactions that remove reactive oxygen species such as hydrogen peroxide and organic hydroperoxides: The thyroid gland and every cell that uses thyroid hormone use selenium, which is a cofactor for the three of the four known types of thyroid hormone deiodinases, which activate and then deactivate various thyroid hormones and their metabolites; the iodothyronine deiodinases are the subfamily of deiodinase enzymes that use selenium as the otherwise rare amino acid selenocysteine. It is used in small quantities to counteract the colour due to iron impurities and so to create (apparently) colourless glass. Some of the selenium oxyhalides, such as selenium oxyfluoride (SeOF2) and selenium oxychloride (SeOCl2) have been used as specialty solvents. Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations. [15], Selenium trioxide may be synthesized by dehydrating selenic acid, H2SeO4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide:[17], Hot, concentrated selenic acid can react with gold to form gold(III) selenate.[18]. The regulation of lead in drinking water applications such as in the US with the Safe Drinking Water Act of 1974, made a reduction of lead in brass necessary. Selenium is a semiconductor and is used in photocells. [56], During the electrowinning of manganese, the addition of selenium dioxide decreases the power necessary to operate the electrolysis cells. 6.33714: 6588.125: 86.633: Stull, 1947: Coefficents calculated by NIST from author's data. [81] With so many humans consuming fish as a source of protein, it is important to be aware of the selenium pollution occurring in the oceans they get their fish from so we know what we are putting in our bodies. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. The Vapor Pressure of Germanium Dioxide Kinetics and Diffusing Species in the Reaction between Molybdenum and Selenium Vapor Closed-Tube Chemical Transport of VxSe2 by Iodine. point below the vaporization temperature, or if it is soluble in an inert solvent with vapor pressure similar to that of the precursor. In the Se8 rings, the Se-Se distance is 233.5 pm and Se-Se-Se angle is 105.7° . Selenium is found in metal sulfide ores, where it partially replaces the sulfur. 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