Final answer:
CFC refrigerants contain chlorine, fluorine, and carbon. Used widely in the past, CFCs have been phased out due to their ozone-depleting characteristics, leading to the introduction of safer alternatives like HFCs and HCFCs.
Step-by-step explanation:
CFC refrigerants are so named because they contain the elements chlorine (Cl), fluorine (F), and carbon (C). Chlorofluorocarbons, commonly known by the brand name Freon, are synthesized chemical compounds formerly used widely in refrigeration, aerosols, and as solvents. Their structure involves carbon atoms surrounded by chlorine and fluorine atoms. Examples include chlorofluorocarbon-11 (CFC-11), chlorofluorocarbon-12 (CFC-12), and many others listed with varying numbers of chlorine and fluorine atoms.
The production and usage of CFCs have been largely phased out due to their harmful effects on the ozone layer, which protects Earth from the sun's ultraviolet radiation. When CFCs reach the upper atmosphere, ultraviolet radiation breaks them down and releases chlorine atoms that deplete the ozone. This issue led to the adoption of the Montreal Protocol, which regulates substances that deplete the ozone layer, prompting the phase-out of CFCs and the introduction of alternative compounds such as hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs).