Freon: Definition and Much More from Answers.com

Trademark for any of several organic compounds containing fluorine (fluorocarbons) and sometimes chlorine (chlorofluorocarbons, or CFCs). Nonflammable, nontoxic, and noncorrosive, they have low boiling points, which makes them useful as refrigerants. By the mid-1970s they were in wide use in refrigeration and air conditioning systems, as blowing agents for plastic foams, as fire-extinguishing agents, and in aerosol sprays. Evidence has accumulated that decomposition of CFCs in the stratosphere destroys ozone there (see ozone layer), so most of their uses have been banned. International agreements signed by most of the industrialized countries have called for the phasing out of CFC use.

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(frē'ŏn) [trade name], any one of a special class of chemical compounds that are used as refrigerants, aerosol propellants, and solvents. These compounds are haloalkanes, i.e., halogen derivatives of saturated hydrocarbons (see alkane). Every Freon contains at least some fluorine in its molecule, and most contain chlorine or bromine as well. Freons are generally colorless, odorless, nontoxic, noncorrosive, nonflammable, and chemically unreactive. The most commonly used is Freon-12, or dichlorodifluoromethane (CCl₂F₂), which boils at −29.8°C and is thus a gas at ordinary temperatures and pressures. It is prepared by the reaction of carbon tetrachloride with hydrogen fluoride in the presence of a catalyst. There are a number of other Freons. Some of those containing bromine in their molecules are used in fire extinguishers. See also chlorofluorocarbons.

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