[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is an odorless yellow solid. Insoluble in water and denser in water. Sinks in water. (USCG, 1999)"}, {"from": "gpt", "value": "[C][=Branch1][C][=O][Branch1][=Branch1][C][=Branch1][C][=O][O-1][O-1].[Fe+2]"}]