Disodium of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid ( HEDPNa2 ) CAS No.:7417-83-7 Molecular Formula:C2H7O7P2Na2 Disodium of ... 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid ( HEDPNa2 )CAS No.:7417-83-7Molecular Formula:C2H7O7P2Na2Disodium of 1-Hydroxy ... water. Disodium of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid ( HEDPNa2 )