[{"from": "human", "value": "Describe this molecule. [C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=C][C][=Branch1][=Branch1][=C][C][=C][Ring1][=Branch1][Cl]"}, {"from": "gpt", "value": "The molecule is a commercial mixture of PCBs with an average chlorine content of 21%. It is composed of mainly monochlorobiphenyls (60.06%), and also includes bi-, tri, tetra-, and pentachlorinated homologs. Polychlorinated biphenyls (PCBs) are a group of 209 synthetic organic compounds with 1-10 chlorine atoms attached to biphenyl. PCBs were manufactured as commercial mixtures but banned in the 1970's because they were found to bioaccumulate in the environment and cause harmful health effects. However, PCBs do not break down readily and are still found in the environment. (L4)"}]