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PCBs are derived from biphenyl, which has the formula C 12 H 10, sometimes written (C 6 H 5) 2.In PCBs, some of the hydrogen atoms in biphenyl are replaced by chlorine atoms. There are 209 different chemical compounds in which one to ten chlorine atoms can replace hydrogen at
This is a complete list of polychlorinated biphenyl (PCB) congeners. Chemical structure of PCBs. The possible positions of chlorine atoms on the benzene rings are denoted by numbers assigned to the carbon atoms.
A group of carcinogenic organic compounds, polychlorinated biphenyls (PCBs), is an example of a congener grouping. The number and locations of Cl groups can vary. In chemistry, congeners are chemical substances "related to each other by origin, structure, or function". [1]
A printed circuit board (PCB), also called printed wiring board (PWB), is a laminated sandwich structure of conductive and insulating layers, each with a pattern of traces, planes and other features (similar to wires on a flat surface) etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive ...
Michigan Chemical Corporation (MCC) in St. Louis, Michigan, which was then owned by Velsicol Chemical Corporation, was a major producer of the FireMaster range of PBB-based flame retardants. FireMaster BP-6 (a yellow-brown powder) is a mixture of many different PBB congeners with 2,2',4,4',5,5'-hexabromobiphenyl and 2,2',3,4,4',5,5 ...
Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene [4] or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one hydrogen (the site at which it is attached) may use the prefixes xenyl or diphenylyl.
Incorrect selection can affect long-term reliability of the circuit board as well as cause processing and cost problems. [8] The most common [citation needed] standards for conformal coating are IPC A-610 [9] and IPC-CC-830. [10] These standards list indications of good and bad coverage and describe various failure mechanisms, such as dewetting.
General chemical structure of PCDFs, where 1 ≤ n+m ≤ 8 Structures of the ten 2,3,7,8-substituted PCDF congeners that are toxicologically of most relevance Polychlorinated dibenzofurans ( PCDFs ) are a family of organic compounds with one or several of the hydrogens in the dibenzofuran structure replaced by chlorines.