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|Section2= |Section4= |Section5= }} Chromium trioxide is an inorganic compound with the formula CrO3. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. This compound is a dark-purple solid under anhydrous conditions, bright orange when wet and which dissolves in water concomitant with hydrolysis. Millions of kilograms are produced annually, mainly for electroplating. Chromium trioxide is a powerful oxidiser and a suspected carcinogen. ==Production, structure, and basic reactions== Chromium trioxide is generated by treating sodium chromate or the corresponding sodium dichromate with sulfuric acid:〔 :H2SO4 + Na2Cr2O7 → 2 CrO3 + Na2SO4 + H2O Approximately 100M kg are produced annually by this or similar routes.〔 The solid consists of chains of tetrahedrally coordinated chromium atoms that share vertices. Each chromium center, therefore, shares two oxygen centers with neighbors. Two oxygen atoms are not shared, giving an overall stoichiometry of 1:3. : The structure of monomeric CrO3 has been calculated using density functional theory, and is predicted to be pyramidal (point group C3v) rather than planar (point group D3h). : Chromium trioxide decomposes above 197 °C liberating oxygen eventually giving Cr2O3: :4 CrO3 → 2 Cr2O3 + 3 O2 It is used in organic synthesis as an oxidant, often as a solution in acetic acid,〔 or acetone in the case of the Jones oxidation. In these oxidations, the Cr(VI) converts primary alcohols to the corresponding carboxylic acids and secondary alcohols to ketones. The reactions are given below: * Primary alcohols ::4 CrO3 + 3 RCH2OH + 12 H+ → 3 RCOOH + 4 Cr3+ + 9 H2O * Secondary alcohols ::2 CrO3 + 3 R2CHOH + 6 H+ → 3 R2C=O + 2 Cr3+ + 6 H2O 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chromium trioxide」の詳細全文を読む スポンサード リンク
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