Thermochemical study of the complex formation of mercury(II) with nitrilotriacetic acid in an aqueous solution

The formation constant of the Hg(Nta)24− complex, where Nta3− is the nitrilotriacetate ion, is determined by pH-metric titration at 298.15 K and ionic strength I = 0.5 (KNO3) (logβ = 21.49 ± 0.10). The thermal effects for the formation of the Hg(NTa)i2−3i complexes (i = 1, 2) are determined by a direct calorimetric method (−56.69 ± 1.04 and −85.88 ± 1.32 kJ/mol for i = 1 and 2, respectively).