Solubility of alkali and alkali earth salts of dihydrogen ethylenediaminetetraacetate in aqueous solutions

The solid metal−EDTA compounds K2H2Y·2H2O, MgH2Y·6H2O, CaH2Y·2H2O, SrH2Y·2H2O, and BaH2Y·3H2O (H2Y2- is dihydrogen ethylenediaminetetraacetate anion) prepared from aqueous media were characterized by elemental analysis, IR spectrometry, and thermogravimetry (TG). The solubilities of these EDTA salts and reagent grade disodium salt (Na2H2Y·2H2O) in water at 25.0 °C were determined by potentiometric titrations with NaOH using a combined glass electrode. The infrared spectra showed that metal ions do not form chelates with EDTA in the studied salts.