... -Diphosphonic Acid Dequest 2016/2016DG Molecular weight: 294 (HEDP Na4)Tetra sodium of 1-Hydroxy Ethylidene-1,1-Diphosphonic AcidProperties:Dequest ... PO43-) % 52.0-54.018.4-20.4Fe, ppm 35.0max20maxDry weight loss,% 15max--density(20°C)g/cm3 --1.26-1 ... eye and skin, once contacted, flush with water. (HEDP Na4)Tetra sodium of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid