Chromium plating with hexavalent chromium electrolyte
Chrome plating

As we saw earlier, chromium can be found in oxidation state 6. The aqueous solution of chromium trioxide (chromic anhydride) is called chromic acid. In solution in water, depending on the CrO ₃ concentration C, different compounds can be found [3] (figure 2 ):

Concentration (mol/L) Nature of complex

C < 10 ^–2 ${\text{HCrO}}_4^{-}$