(1-Hydroxyethylidene)-1,1-diphosphonic acid2809-21-4100 % similar Etidronate disodium7414-83-762 % similar Tetrasodium etidronate3794-83-041 % similar Clodronate10596-23-339 % similar P,P′-(3-Amino-1-hydroxypropylidene)bis[phosphonic acid]40391-99-934 % similar Alendronic acid66376-36-132 % similar Ibandronate114084-78-532 % similar