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Chromate salts contain the chromate anion, CrO 2− 4. Dichromate salts contain the dichromate anion, Cr 2 O 2− 7. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.
The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [1] [2]. Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
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 2005–06, potassium dichromate was the 11th-most-prevalent allergen in patch tests (4.8%). [12] Potassium dichromate is one of the most common causes of chromium dermatitis; [13] chromium is highly likely to induce sensitization leading to dermatitis, especially of the hand and forearms, which is chronic and difficult to treat ...
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. [1] [2] Ion associates are classified, according to the number of ions that associate with each other, as ion pairs, ion triplets, etc. Ion pairs are also classified according to the nature of the interaction as contact, solvent-shared or ...
Salts form upon evaporation of their solutions. [9] Once the solution is supersaturated and the solid compound nucleates. [9] This process occurs widely in nature and is the means of formation of the evaporite minerals. [10] Insoluble salts can be precipitated by mixing two solutions, one with the cation and one with the anion in it.
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 ]