What refrigerants does not contain chlorine?

Refrigerants that do not contain chlorine include hydrocarbons like propane and butane, as well as some newer synthetic refrigerants such as HFCs (hydrofluorocarbons) and HFOs (hydrofluoroolefins). These chlorine-free refrigerants are considered more environmentally friendly as they do not contribute to ozone depletion like chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).