Thermodynamics of mixed-ligand complex formation of samarium(III) and cerium(III) ethylenediaminetetraacetates with various ligands in aqueous solution

The thermodynamic parameters of reaction (logK, Δ_r G ⁰, Δ_r H, Δ_r S) are determined for the mixed-ligand complex formation of SmEdta^? and CeEdta^? with glycinate, iminodiacetate, aspartate, and nitrilotriacetate ions in aqueous solution at 298.15 K and ionic strength of I = 0.5 (KNO₃). Based on these thermodynamic data, the most likely coordination modes are suggested for the complexone and the ancillary ligand in the mixed-ligand complexes.