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Selenite salts can be prepared by neutralizing solutions of selenous acid, which is generated by dissolving selenium dioxide in water. The process proceeds via the hydrogenselenite ion, HSeO − 3. Most selenite salts can be formed by heating the metal oxide with selenium dioxide, e.g.: Na 2 O + SeO 2 → Na 2 SeO 3
Selenium is a chemical element; it has the symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust.
Selenite (ion), anion is a selenium oxoanion with the chemical formula SeO 3 2−. Selenous acid, the conjugate acid, with the formula H 2 SeO 3; Salts of this anion: Silver selenite, an inorganic compound of formula Ag 2 SeO 3; Sodium selenite, a salt, a colourless solid, and the most common water-soluble selenium compound
Selenium is a nutrient that is naturally present in many foods, added to others and is also available as a dietary supplement in pill, powder and liquid form, explains Perri Halperin, a ...
Ⓚ Of 103 elements shown in the image, just ten form anions, all of these being in the p-block: arsenic; the five chalcogens: oxygen, sulfur, selenium, tellurium, polonium; and the four halogens: fluorine, chlorine, bromine, and iodine Ⓛ Anion-only elements are confined to oxygen and fluorine.
Selenium forms two oxides: selenium dioxide (SeO 2) and selenium trioxide (SeO 3). Selenium dioxide is formed by the reaction of elemental selenium with oxygen: [5] + It is a polymeric solid that forms monomeric SeO 2 molecules in the gas phase. It dissolves in water to form selenous acid, H 2 SeO 3.
A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+. The solvation number , n , determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table .
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.