Chromic acid pyridine salt, molecular formula c5h4n Hcro3cl, referred to as PCC, is the abbreviation of Pyridinium chlorochromate. A mild oxidizer, orange-yellow crystals. Used to limit alcohol oxidation to aldehyde, the disadvantage of PCC is that the reaction time is too long and the PCC is toxic. Invented by E.j.corey. The reagent itself is weakly acidic, so it is often used in conjunction with buffers such as sodium acetate.