acids corresponding to Cr(VI): chromic acid, H2CrO4, and the isopolychromic acids—dichromic acid, H2Cr2O7, trichromic acid, H2Cr3O10, and tetrachromic acid, H2Cr4O13. They are formed by dissolving chromium trioxide, CrO3, in water. Chromic acid, a red crystalline compound, is isolated in the free state by cooling saturated aqueous solutions of chromium trioxide. It is a medium-strength electrolyte. The isopolychromic acids exist in the form of red aqueous solutions.
Chromic acids are strong oxidizing agents. Chromate salts correspond to chromic acid, and isopolychromate salts correspond to isopolychromic acids. Solutions of chromic acid are used in chromium plating and the electrolytic production of chromium. Chromic acids are poisonous. (For information on the safety rules for handling these acids, see.)