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- Selenium (Se) Metal & Powder Synonyms:
selenium metal, selenium powder, selenium powder black, selenium shot, selenium crystal, CAS# 7782-49-2,
Chemical Name: Selenium
Chemical Formula: Se
Amorphous selenium is either a reddish powder or a black, vitreous solid; crystalline selenium is either red or gray, depending on the crystal structure. This element resembles sulfur in its various forms and in its compounds. Selenium has many electrical properties, being both photovoltaic, where light converts to electricity, and photoconductive, where electrical resistance decreases with increases illumination. Below its melting point, selenium is p-type semiconductor.
99.6% to 99.999%
Shot, granules, and powder
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Atomic Number
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34
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Molecular Weight (g/mol.)
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78.96
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Apparent Density (g/cm3)
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4.79
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Bulk Density (g/cm3)
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Specific Heat @25°C (cal/g-°C)
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.084
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Melting Point (°C)
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217
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Boiling Point (°C)
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685
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Thermal Conductivity (cal/s-cm°C)
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1.0x10-4
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Mohs Hardness @20°C
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2.0
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Surface Area (m2/g)
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pH
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EC Number
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034-001-00-2
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RTECS Number
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VS7700000
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Crystallography
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hexagonal structure
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Production of light sensitive surfaces (photocopier machine drums, decolorization of container glass, tinting of architectural glass), pigments for plastics, glass, ceramics and paint, additive to stainless steel; used in manufacture of semiconductors and rectifiers; additive to pharmaceutical and nutritional preparations.
Drums, bulk bags or loose bulk
Listed. For further information please call the E.P.A. at +1.202.554.1404
CAS# 7782-49-2
2658 (powder)
"a) Although selenium is an essential trace element, it is toxic if taken in excess. Exceeding the Tolerable Upper Intake Level of 400 micrograms per day can lead to selenosis.[9] Symptoms of selenosis include a garlic odour on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability and neurological damage. Extreme cases of selenosis can result in cirrhosis of the liver, pulmonary edema and death.
b) Elemental selenium and most metallic selenides have relatively low toxicities because of their low bioavailability. By contrast, selenate and selenite are very toxic, and have modes of action similar to that of arsenic. Hydrogen selenide is an extremely toxic, corrosive gas. Selenium also occurs in organic compounds such as dimethyl selenide, selenomethionine, selenocysteine and methylselenocysteine, all of which have high bioavailability and are toxic in large doses. Nano-size selenium has equal efficacy, but much lower toxicity.
c) Selenium poisoning of water systems may result whenever new agricultural runoff courses through normally dry undeveloped lands. This process leaches natural soluble selenium compounds (such as selenates) into the water, which may then be concentrated in new "wetlands" as the water evaporates. High selenium levels produced in this fashion have been found to have caused certain congenital disorders in wetland birds." Source: Wikipedia
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