[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule appears as a colorless liquid with a pungent odor. Insoluble in water. Very toxic by ingestion and inhalation. Vapors are heavier than air. Used to make other chemicals."}, {"from": "gpt", "value": "[C][C][Branch1][C][C][N][=C][=O]"}]