[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is the organic sodium salt of dimethylarsinate. It has a role as a buffer and a herbicide. It contains a dimethylarsinate."}, {"from": "gpt", "value": "[C][As][=Branch1][C][=O][Branch1][C][C][O-1].[Na+1]"}]