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Two crystalline forms are known, both being very similar to the corresponding potassium sulfate. Orthorhombic β-K 2 CrO 4 is the common form, but it converts to an α-form above 666 °C. [ 1 ] These structures are complex, although the chromate ion adopts the typical tetrahedral geometry.
Potassium dichromate, K 2 Cr 2 O 7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health.
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 chromium is oxidized to the hexavalent form, while the iron forms iron(III) oxide, Fe 2 O 3: 4 FeCr 2 O 4 + 8 Na 2 CO 3 + 7 O 2 → 8 Na 2 CrO 4 + 2 Fe 2 O 3 + 8 CO 2. Subsequent leaching of this material at higher temperatures dissolves the chromates, leaving a residue of insoluble iron oxide.
This page contains tables of azeotrope data for various binary and ternary mixtures of solvents. The data include the composition of a mixture by weight (in binary azeotropes, when only one fraction is given, it is the fraction of the second component), the boiling point (b.p.) of a component, the boiling point of a mixture, and the specific gravity of the mixture.
The water molecule is amphoteric in aqueous solution. It can either gain a proton to form a hydronium ion H 3 O +, or else lose a proton to form a hydroxide ion OH −. [7] Another possibility is the molecular autoionization reaction between two water molecules, in which one water molecule acts as an acid and another as a base. H 2 O + H 2 O ...
Many minerals are assumed to form via olation. Aquo ions of divalent metal ions are less acidic than those of trivalent cations. The hydrolyzed species often exhibit very different properties from the precursor hexaaquo complex. For example, water exchange in [Al(H 2 O) 5 OH] 2+ is 20000 times faster than in [Al(H 2 O) 6] 3+.
The disproportionation of hydrogen peroxide into water and oxygen catalysed by either potassium iodide or the enzyme catalase: 2 H 2 O 2 → 2 H 2 O + O 2 In the Boudouard reaction , carbon monoxide disproportionates to carbon and carbon dioxide .