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The chromate and dichromate ions are fairly strong oxidizing agents. 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.
A dianion is an anion with a net charge of −2. While there exist many stable molecular dianions, such as BeF 4 2− and MgF 4 2− , [ 1 ] thus far no stable atomic dianion has been found: Electron shielding and other quantum mechanical effects tend to make the addition of another electron to an atomic anion unstable.
The dichromate ion, Cr 2 O 2− 7, is predominant in more concentrated solutions, except at high pH. The species H 2 CrO 4 and HCr 2 O − 7 are not shown as they are formed only at very low pH. Predominance diagrams can become very complicated when many polymeric species can be formed, [ 10 ] such as in vanadates , molybdates , and tungstates .
In a similar fashion, the DBA dianion is also capable of activating carbon dioxide. [14] Since the DBA dianion is isoelectronic with anthracene, the first step involves the formal [4+2] cycloaddition, which resembles the reaction with benzophenone. After the formation of the C-O-bridged intermediate, it was proposed that the heterolytic ...
Sodium dichromate is the inorganic compound with the formula Na 2 Cr 2 O 7. However, the salt is usually handled as its dihydrate Na 2 Cr 2 O 7 ·2 H 2 O . Virtually all chromium ore is processed via conversion to sodium dichromate and virtually all compounds and materials based on chromium are prepared from this salt. [ 1 ]
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Chromic acid is jargon for a solution formed by the addition of sulfuric acid to aqueous solutions of dichromate. It consists at least in part of chromium trioxide. [3] The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium ...
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