[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a hydrochloride salt form of dichlorophenarsine, an arsenic-containing agent formerly used in the treatment of syphilis."}, {"from": "gpt", "value": "[C][=C][C][=Branch1][=C][=C][Branch1][#Branch2][C][=C][Ring1][=Branch1][As][Branch1][C][Cl][Cl][N][O].[Cl]"}]