Caption:
Chromium oxidation states. Solutions of some common salts of chromium. Chromium chloride CrCl3 (violet) and chromium nitrate Cr(NO3)3 (green) illustrate chromium in oxidation state +3. In potassium chromate K2CrO4 (yellow) and potassium dichromate K2Cr2O7 (orange) chromium has an oxidation state of +6.