[{"from": "human", "value": "What can you tell me about this molecule? [C][=Branch1][C][=O][Branch1][C][Cl][Cl]"}, {"from": "gpt", "value": "The molecule is a synthetic formaldehyde derivative with both hydrogens substituted by chlorine. Phosgene is used in the manufacture of other chemicals, pesticides, and pharmaceuticals. It can also be used to separate ores, and has been used as a chemical warfare agent. It is characterized as a colorless to light yellow gas at room temperature and normal pressure or as a liquid under pressure or with refrigeration, with an odor of freshly cut hay. Exposure occurs by inhalation, ingestion, or contact."}]