[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule appears as a fine white to cream crystalline solid. Toxic by ingestion, inhalation or skin absorption. Denser than water."}, {"from": "gpt", "value": "[C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][Hg].[O]"}]