The primary chromium ore is that the mixed metal oxide chromite, FeCr2O4, found as brittle metallic black crystals or granules.

The redox potential shows that chromates are the weaker oxidant in alkaline solution than in acid solution.ĬrO 2−4 + 4 H 2O + 3 e− → Cr(OH)3 + 5 OH− In alkaline solution chromium(III) hydroxide is produced. In acid solution, there is the production of aquated Cr3+ ion.Ĭr 2O 2−7 + 14 H+ + 6 e− → 2Cr3+ + 7H 2O ε0 = 1.33 V Commonly three electrons are added to a chromium atom, reducing it to oxidation number +3. The chromate and dichromate ions are good strong oxidizing agents. In solution, chromate and dichromate anions exist in equilibrium. But the ion of dichromate can become predominant in acidic solutions. The chromate ion is that the predominant species in alkaline solutions. The position of the equilibrium depends on both pH and therefore the analytical concentration of chromium. In a solution, chromate ions are often interconvertible. Chromate salt of heavy metals, lanthanides, and alkaline-earth metal metals are only very slightly soluble in water and are used as pigments. The Simplified molecular-input line-entry system (SMILES) ()(=O)=OĬhromate is employed in chrome plating to guard metals against corrosion and to enhance paint adhesion.

Potassium chromate may be a common laboratory chemical and sodium chromate is vital industrially. Potassium chromate may be a Chemical and compound with the formula K2CrO4. However, dichromate salts consist of the dichromate anion, Cr ₂O²⁻₇. 3 Solved Examples for Chromate Formula Chromate FormulaĬhromate salts contain the chromate anion, CrO²-₄.

Chromium charge in dicromate