CFCs
Definition and meaning of CFCs in chemistry.
CFCs (chlorofluorocarbons) are synthetic organic compounds containing carbon, fluorine, and chlorine atoms. They were widely used as refrigerants, aerosol propellants, and solvents in the late 20th century but are now phased out due to their destructive effect on the stratospheric ozone layer.
In more detail
When CFCs are released into the atmosphere, they slowly diffuse upward to the stratosphere over several decades. In the stratosphere, ultraviolet radiation breaks down CFC molecules, releasing highly reactive chlorine atoms. Each chlorine atom can destroy thousands of ozone molecules through a catalytic chain reaction, creating ozone holes especially over the Antarctic and Arctic regions. The Montreal Protocol of 1987 initiated a global phase-out of CFC production, and CFCs also contribute to climate change as potent greenhouse gases.
Key facts
| Common Example | CFC-12 (CF2Cl2) - dichlorodifluoromethane |
|---|---|
| Primary Threat | Ozone depletion in the stratosphere |
| Status | Phased out globally under the Montreal Protocol (1987) |
| Field | General Chemistry |
CFC-12 (dichlorodifluoromethane, CF2Cl2) was the most common refrigerant used in car air conditioning and home refrigerators until the 1990s, when it was replaced by safer alternatives like hydrofluorocarbons (HFCs).
Frequently asked questions
Why are CFCs so harmful to the ozone layer?
When CFC molecules reach the stratosphere, ultraviolet light breaks them apart, releasing chlorine atoms. Each chlorine atom can destroy thousands of ozone molecules before being deactivated, amplifying the damage.
Were CFCs completely phased out?
Yes, most CFCs were eliminated under the Montreal Protocol starting in the 1990s. They were replaced by hydrofluorocarbons (HFCs) and more recently hydrofluoroolefins (HFOs), which do not harm the ozone layer.