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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]
Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K 2 SeO 4) and sulfur trioxide (SO 3). [7] Salts of selenous acid are called selenites. These include silver selenite (Ag 2 SeO 3) and sodium selenite (Na 2 SeO 3). Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
[3] [4] It is suitable for food and laboratory uses. Reagent grade is almost as stringent as the ACS grade. USP grade meets the purity levels set by the United States Pharmacopeia (USP). USP grade is equivalent to the ACS grade for many drugs. NF grade is a purity grade set by the National Formulary (NF). NF grade is equivalent to the ACS grade ...
USP establishes documentary (written) and reference (physical) standards for medicines, food ingredients, dietary supplement products, and ingredients. These standards are used by regulatory agencies and manufacturers to help to ensure that these products are of the appropriate identity, as well as strength, quality, purity, and consistency.
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. [3] Se + 2HNO 3 → H 2 SeO 3 + NO + NO 2 H 2 SeO 3 + Na 2 CO 3 → Na ...
Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K 2 SeO 4) and sulfur trioxide (SO 3). [25] Salts of selenous acid are called selenites. These include silver selenite (Ag 2 SeO 3) and sodium selenite (Na 2 SeO 3). Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
Sodium phosphate; see trisodium phosphate – Na 3 PO 4; Sodium selenate – Na 2 O 4 Se; Sodium selenide – Na 2 Se; Sodium selenite – Na 2 SeO 3; Sodium silicate – Na 2 SiO 3; Sodium sulfate – Na 2 SO 4; Sodium sulfide – Na 2 S; Sodium sulfite – Na 2 SO 3; Sodium tartrate – C 4 H 4 Na 2 O 6; Sodium tellurite – Na 2 TeO 3 ...
Selenite refers to the anion with the chemical formula Se O 2− 3. It is the oxyanion of selenium. It is the selenium analog of the sulfite ion, SO 2− 3. Thus selenite is pyramidal and selenium is assigned oxidation state +4. Selenite also refers to compounds that contains this ion, for example sodium selenite Na 2 SeO 3 which is a common ...