[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule appears as yellow crystals melting at15 \u00b0C. Hence often encountered as a light yellow liquid with a weak sour odor. Vapor has a green color and burns with a violet flame."}, {"from": "gpt", "value": "[C][=Branch1][C][=O][C][=O]"}]