Your air conditioner uses refrigerant, which is a chemical molecule. It absorbs heat from the surroundings and produces cool air after passing via compressors and evaporators. There are three types, and using the incorrect one can cause damage to your air conditioner because they are not interchangeable.
CFC = ChloroFluoroCarbons.
HCFC = HydroChloroFluoroCarbons.
HFC = HydroFluoroCarbons.
FC = FluoroCarbons.
HC = HydroCarbons.
NH3 = Ammonia.
CO2 = Carbon Dioxide
A refrigerant is a chemical molecule that acts as a heat carrier in the refrigeration cycle, changing from gas to liquid and then back to gas. Refrigerators/freezers, air conditioning, and fire suppression systems all require refrigerants.
Freon is a non-combustible refrigerant that is used in air conditioning systems. This freon goes through a series of evaporation cycles in order to produce cool air that may be circulated throughout your AC system.
R-410A, R-407C, and R-134a are the most prevalent hydrofluorocarbon (HFC) refrigerants for new commercial air conditioning systems in the United States today, but R22 systems are still in use.