[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C][=Branch1][C][=O][O].[C][C][=Branch1][C][=O][O].[O][=U][=O]"}, {"from": "gpt", "value": "The molecule is a chemical compound of uranium. It is used as a negative stain in electron microscopy. Uranium is a chemical element that has the symbol U and atomic number 92. It is a normal part of rocks, soil, air, and water, and occurs in nature in the form of minerals. (L248, L249, L256)"}]