[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is an organic magnesium salt of propionic acid. It is used in animal feedstuff and also as a preservative in cosmetics."}, {"from": "gpt", "value": "[C][C][C][=Branch1][C][=O][O-1].[C][C][C][=Branch1][C][=O][O-1].[Mg+2]"}]