[{"from": "human", "value": "Provide a description of this molecule. [C][C][Branch1][C][O][Branch1][=Branch2][P][=Branch1][C][=O][Branch1][C][O][O][P][=Branch1][C][=O][Branch1][C][O][O]"}, {"from": "gpt", "value": "The molecule is a 1,1-bis(phosphonic acid) that is (ethane-1,1-diyl)bis(phosphonic acid) having a hydroxy substituent at the 1-position. It inhibits the formation, growth, and dissolution of hydroxyapatite crystals by chemisorption to calcium phosphate surfaces. It has a role as a bone density conservation agent, a chelator and an antineoplastic agent. It is a conjugate acid of an etidronic acid(2-)."}]