|polychlorinated biphenyl (ˌpɒlɪˈklɔːrɪˌneɪtɪd)|
|PCB any of a group of compounds in which chlorine atoms replace the hydrogen atoms in biphenyl: used in industry in electrical insulators and in the manufacture of plastics; a toxic pollutant that can become concentrated in animal tissue|
polychlorinated biphenyl pol·y·chlo·rin·at·ed biphenyl (pŏl'ē-klôr'ə-nā'tĭd)
any of a class of organohalogen compounds prepared by the reaction of chlorine with biphenyl. A typical mixture of PCBs may contain over 100 compounds and is a colourless, viscous liquid. The mixture is relatively insoluble in water, is stable at high temperatures, and is a good dielectric (electrical insulator). Because of these qualities, PCBs are particularly useful as lubricants, heat-transfer fluids, and fire-resistant insulating fluids in transformers and capacitors.
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