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Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO 4 ·2H 2 O. Selenite contains no selenium, the similar names both derive from Greek selḗnē (σελήνη 'Moon').
A selenate selenite is a chemical compound or salt that contains selenite and selenate anions ... properties references Boroseleniteselenate B 2 Se 3 O 10: 1:2 monoclinic
Sodium selenate is produced by oxidation of selenium, first with nitric acid, producing selenous acid.The selenous acid is neutralized to form sodium selenite.The sodium selenite is oxidized in a basic medium hydrogen peroxide to form a selenate, which is then spray-dried.
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]
The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium; selenide is even more reduced than elemental selenium. [6] The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient.
The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. [140] Hydrogen selenide is an extremely toxic, corrosive gas. [ 141 ] Selenium also occurs in organic compounds, such as dimethyl selenide, selenomethionine , selenocysteine and methylselenocysteine , all of which have high bioavailability and ...
According to the New York Times, here's exactly how to play Strands: Find theme words to fill the board. Theme words stay highlighted in blue when found.
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