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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 +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium ...
Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH) 3. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids. [2] In alkali: Cr(OH) 3 + OH − → CrO − 2 + 2 H 2 O In acid: Cr(OH) 3 (OH 2) 3 + 3 H + → Cr(OH 2) 6 3+
Chromium is a chemical element; it has symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. [10] Chromium is valued for its high corrosion resistance and hardness.
A carbonate is a salt of carbonic acid, (H 2 CO 3), [2] characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO 2− 3. The word "carbonate" may also refer to a carbonate ester , an organic compound containing the carbonate group O=C(−O−) 2 .
For lab and small scale preparations a mixture of chromite ore, sodium hydroxide and sodium nitrate reacting at lower temperatures may be used (even 350 C in the corresponding potassium chromate system). [2] Subsequent to its formation, the chromate salt is converted to sodium dichromate, the precursor to most chromium compounds and materials. [3]
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 ammines of chromium(III) and cobalt(III) are of historic significance. Both families of ammines are relatively inert kinetically, which allows the separation of isomers. [ 11 ] For example, tetraamminedichlorochromium(III) chloride, [Cr(NH 3 ) 4 Cl 2 ]Cl , has two forms - the cis isomer is violet, while the trans isomer is green.
C. Chrome alum; Chromite (compound) Chromium acetate hydroxide; Chromium nitride; Chromium(III) 2-ethylhexanoate; Chromium(III) acetate; Chromium(III) acetylacetonate