PCC, or pyridinium chlorochromate, is an organic chemistry reagent. The reagent is a red-orange salt that is used to oxidize primary and secondary alcohols to aldehydes and ketones. Over-oxidation can occur if too much PCC is used, resulting in the alcohols being oxidized to carboxylic acids.
PCC oxidizes compounds via an elimination reaction. Carbon-oxygen single bonds turn into carbon-oxygen double bonds, while a leaving group in the compound will be eliminated. PCC causes the leaving group to disconnect from the organic compound and attack the oxygen to form an intermediate pyridinium salt and a chromate-oxygen bond. After the PCC completely reacts, a carbon-oxygen double bond forms.