[{"from": "human", "value": "Provide a brief overview of this molecule. [O][P+1][=Branch1][C][=O][O][P+1][=Branch1][C][=O][O]"}, {"from": "gpt", "value": "The molecule is a phosphorus oxoacid and an acyclic phosphorus acid anhydride. It is a conjugate acid of a diphosphonate(1-)."}]