Selenic Acid - Selenite

H ₂ SeO ₄ (144.98). Selenic acid is a common name allowed by IUPAC nomenclature. The systematic name according to the addition nomenclature is dihydroxidodioxidoselenium, in accordance with the structure [SeO ₂ (OH) ₂ ]. It can be obtained by oxidizing an aqueous solution of SeO ₂ with H ₂ O ₂ and concentrating it. It can also be obtained by reacting PbSeO ₄ with H ₂ S. It is an orthorhombic crystal. There is a SeO ₄ with a regular tetrahedral structure. The Os are mutually bonded by OH...O. Se-O1.61 Å. OH...O 2.61, 2.68 Å. Melting point 58 °C. It decomposes at 260 °C to SeO ₂ , H ₂ O, and O _2. It is easily soluble in water. It also forms di-, tetra-, and hexahydrates. It is a strong acid with a p K ₂ of 1.75 (25 °C) similar to sulfuric acid, and has effects such as dehydrating and carbonizing organic matter. It is a stronger oxidizing agent than sulfuric acid, and will oxidize HX (X = Cl, Br, I), H ₂ S, formic acid, oxalic acid, S, P, etc. It also dissolves Ag, Au, Pd, etc. "Selenium and its compounds" are classified as poisonous substances under the Poisonous and Deleterious Substances Control Law, as Class 1 designated chemical substances under the Law Concerning the Reporting and Management of Releases of Chemical Substances and Promotion of Their Management, and as dangerous and harmful substances requiring notification of their names, etc. under the Industrial Safety and Health Law. [CAS 7783-08-6]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

H₂SeO₄(144.98)．セレン酸はIUPAC命名法の許容する慣用名．付加方式命名法による体系名は，構造[SeO₂(OH)₂]に従ってジヒドロキシドジオキシドセレン(dihydroxidodioxidoselenium)．SeO₂の水溶液をH₂O₂で酸化後，濃縮すると得られる．PbSeO₄とH₂Sとの反応などでも得られる．斜方晶系の結晶．正四面体型構造のSeO₄が存在する．Oは互いにO-H…O結合をしている．Se-O1.61 Å．O-H…O 2.61，2.68 Å．融点58 ℃．260 ℃ で分解して，SeO₂，H₂O，O₂になる．水に易溶．二，四，六水和物もつくる．硫酸に似てpK₂ 1.75(25 ℃)の強い酸で，脱水，有機物を炭化するなどの作用がある．硫酸より強い酸化剤で，HX(X ＝ Cl，Br，I)，H₂S，ギ酸，シュウ酸，S，Pなどを酸化する．Ag，Au，Pdなども溶解する．「セレン及びその化合物」は毒物及び劇物取締法・毒物，化学物質排出把握管理促進法・第一種指定化学物質，労働安全衛生法・名称等を通知すべき危険物及び有害物．[CAS 7783-08-6]

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