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Chromate anions (CrO 2− 4) and dichromate (Cr 2 O 7 2−) anions are the principal ions at this oxidation state. They exist at an equilibrium, determined by pH: 2 [CrO 4] 2− + 2 H + ⇌ [Cr 2 O 7] 2− + H 2 O. Chromium(VI) oxyhalides are known also and include chromyl fluoride (CrO 2 F 2) and chromyl chloride (CrO 2 Cl 2). [6]
4 CrO 3 → 2 Cr 2 O 3 + 3 O 2. It is used in organic synthesis as an oxidant, often as a solution in acetic acid, [9] 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 shown below: Primary alcohols ...
Commonly three electrons are added to a chromium atom, reducing it to oxidation state +3. In acid solution the aquated Cr 3+ ion is produced. Cr 2 O 2− 7 + 14 H + + 6 e − → 2 Cr 3+ + 7 H 2 O ε 0 = 1.33 V. In alkaline solution chromium(III) hydroxide is produced. The redox potential shows that chromates are weaker oxidizing agent in ...
Cr 2 O 3 + 3 CrO 3 → 5 CrO 2 + O 2. Along with many other oxides, it is used as a compound when polishing (also called stropping) the edges of knives, razors, surfaces of optical devices etc. on a piece of leather, balsa, cloth or other material. It is available in powder or wax form, and in this context it is known as "green compound".
The reaction stoichiometry implicates the Cr(IV) species "CrO 2 OH −", which comproportionates with the chromic acid to give a Cr(V) oxide, which also functions as an oxidant for the alcohol. [ 6 ] The oxidation of the aldehydes is proposed to proceed via the formation of hemiacetal -like intermediates, which arise from the addition of the O ...
Each string oxidation-state-number values an oxidation-state-number eg "+3," starts with a space or a newline, followed by; a math minus sign (not a dash) OR; a plus OR; nothing; followed by number, followed by comma (every entry including the last one), a referenced-oxidation-state-number is an oxidation-state-number followed by a <ref ...
This compound is commonly prepared by reacting chromium(III) oxide and potassium hydroxide at 850 °C under argon: [2]. Cr 2 O 3 + 6 KOH → 2 K 3 CrO 4 + H 2 O + 2 H 2. This compound can be prepared other ways such as replacing chromium oxide with potassium chromate.
See also: oxidation states in {{infobox element}} [ edit ] The oxidation states are also maintained in articles of the elements (of course), and systematically in the table {{ Infobox element/symbol-to-oxidation-state }}