Thermodynamic stability parameters for chemical systems in aqueous solution.
Stability constants of metal complexes are extremely important. In theoretical chemistry,
relationships must often be found between such quantities and some acid-base properties of metal
ions and ligands, such as hydrolysis of metal ions, protonation of ligands and metal-ligand
association. The stability constants are often determined at only one ionic strength value and mostly
in not interacting ionic media [1]. However, the stability of species and their percentage formation in
natural aqueous systems are strongly dependent on some factors such as ionic strength, medium
composition, temperature and pH: for example, the ionic strength of natural waters ranges from
about 0,08 mol L-1 for fresh waters to about 0.7 mol L-1 for marine waters and up to 3 mol L-1 for
hyper saline waters; the ionic strength in biological fluids is about 0.16 mol L-1, etc. Therefore, in
addition to the determination of stability constants in pure water or in not interacting ionic media,
for a correct to characterize correctly the natural waters and biological fluids, studies must be
carried out on the dependence of formation constants on the ionic strength. Stability constants are
widely used in analytical chemistry in devising new methods or estimating interfering effects: they
must also be considered in such areas as the kinetics of reaction in solution involving metal
complexes, the biological effects of metal ions, the mobility and the bioavailability in soils and
waters, etc.
1. Martell A.M., Smith R.M., Motekaitis R.J. NIST Standard Reference Database 46, vers.8,
Gaithersburg, 2004.
Some articles published in this topic (since 2000)
1) Gianguzza A., Piazzese D., et al. Complexes of Azelaic and Diethylenetrioxydiacetic Acids with Na+, Mg2+
and Ca2+ in NaCl Aqueous Solutions, at 25 °C. J. Chem. Eng. Data, 45, pp. 15-19, (2000).
2) Gianguzza A., et al. The Interaction of Amino Acids with major constituents of natural waters, at
different ionic strengths. Marine Chemistry, 72, 61-76, (2000).
3) Gianguzza A., et al. Stability-Charge and Stability-Structure relationships in the binding of dicarboxylic
ligands by open-chain polyammonium cations. J. Chem. Eng. Data, Vol. 45, n° 5, 717-723, (2000)
4) Gianguzza A., Piazzese D., et al. Polyacrylate Protonation in Various Aqueous Ionic Media at Different
Temperatures and Ionic Strengths. J. Chem. Eng. Data, 45, n°5, 876-881, (2000)
5) Gianguzza A., Piazzese D., et al. Protonation constants and association of polycarboxylic ligands with the
major components of seawater. J. Chem. Eng. Data, 45, n°6, 996-1000 (2000)
6) Gianguzza A., Piazzese D., et al. Binding of acrylic and sulphonic polyanions by open-chain
polyammonium cations. Talanta, 53, 1241-1248, (2001)
7) Gianguzza A., et al. Hydrolysis and complex formation of (C2H5)2Sn2+, (C2H5)3Sn+ and (C3H7)3Sn+ in
aqueous media simulating the major composition of natural waters. Appl. Organomet. Chem., (2002),
16: 34-43.
8) Gianguzza A., et al. D-Glucuronate Complexes with mono-, di- and triorganotin(IV) compounds.
Potentiometric and Mossbauer spectroscopic investigations. Applied Organomet. Chem. , (2002)
16:294-301.
9) Gianguzza A., et al. Dependence on Ionic Strength of Hydrolysis Constants for Dioxouranium (VI) in
NaCl(aq) and NaNO3(aq), at pH < 6 and t = 25 °C. J. Chem. Eng. Data ,(2002), 47, pp. 533-538.
10) Gianguzza A., Piazzese D., et al. Polyacrylates in Aqueous Solution. The Dependence of Protonation on
Molecular Weight, Ionic Medium and Ionic Strength. React. & Funct. Polymers, 55 (2003), pp. 9-20.
11) Gianguzza A., Piazzese D., et al. Interactions of Diethylene triamino penta acetic (DTPA) and triethylene
tetramino hexacetic acids (TTHA) with major components of natural waters. Anal. Bioanal. Chem.,
(2004), 375: 956-967.
12) Gianguzza, A., Pettignano, A., et al. Interaction of UO22+ with ATP in aqueous ionic media. Biophysical
Chemistry, 117 (2005), 147-153.
13) Gianguzza, A., Pettignano, A., et al. Interaction of Dioxouranium(VI) ion with aspartate and glutamate in
NaClaq at different ionic strengths. J. Chem. Eng. Data, 50, (2005), 1576-1581.
14) Gianguzza, A., Pettignano, A., et al. Interaction of methyltin(IV) compounds with carboxylic ligands. Part
1: Formation and stability of methyltin(IV) – carboxylate complexes and their relevance in speciation
studies of natural waters. Applied Organomet. Chem, 20, 89-98, (2006).
15) Gianguzza A., Piazzese D., et al. Protonation of carbonate in aqueous tetra-alkyl ammonium salts at
25°C. Talanta, 68, 1102-1112, (2006).
16) Gianguzza A., Pettignano A., et al. Interaction of methyltin(IV) compounds with carboxylate ligands. Part
2: formation, thermodynamic parameters, predictive relationships and sequestering ability. Appl.
Organomet. Chem., 22, (2008) 30-38.
17) Gianguzza A., et al. Weak alkali and alkaline earth metal complexes of low molecular weight ligands in
aqueous solution. Coord. Chem. Rev., 252, (2008), 1093-1107.
18) Cataldo S., Gianguzza A., Piazzese D., et al. Interaction of chitosan with low and high molecular weight
carboxylates in aqueous solution. Chem. Spec. Bioavailability, 21(2), (2009), 81-91.
19) Cataldo S., Gianguzza A., Pettignano A., Piazzese D. et al. Solubility and Acid-Base properties and Activity
Coefficients of Chitosan in Different Ionic Media and at different ionic strengths, at T = 25 °C. J.
Molecular Liquids, 148 (2009) 120–126
20) Gianguzza A., Pettignano A., et al. On the complexation of Cu(II) and Cd(II) with polycarboxyl ligands.
potentiometric studies with ISE-H+ , ISE-Cu2+ and ISE-Cd2+. J. Chem. Eng. Data, 2010, 55, 714–722.
21) Gianguzza A., Pettignano A. et al. Interactions of Dioxouranium(VI) with Polyamines in Aqueous
Solution. J. Chem. Eng. Data 2010, 55, 3044–3050.
22) A. Pettignano et al. Formation and stability of cadmium(II)/Phytate complexes by different
electrochemical techniques. Critical analysis of results, J. Sol. Chem., 39 (2010) 179-195.
23) Gianguzza A., et al. Hydrolysis of Monomethyl-, Dimethyl-, and Trimethyltin(IV) Cations in Fairly
Concentrated Aqueous Solutions at I = 1 mol L-1 (NaNO3) and T = 298.15 K. Evidence for the
Predominance of Polynuclear Species. J. Chem. Eng. Data 2011, 56, 1108–1115.
24) Gianguzza A., Pettignano A., et al. Palladium(II) complexes of Aminopolycarboxylic Ligands in Aqueous
Solution. J. Chem. Eng. Data 2011, 56, 4759–4771.
25) Cataldo S., Gianguzza A., Pettignano A, Piazzese D., et al.. Complex Formation of Copper(II) and
Cadmium(II) with Pectin and Polygalacturonic Acid in Aqueous Solution. An ISE-H+ and ISE-Me2+
Electrochemical Study. Int. J. Electrochem. Sci., 7 (2012) 6722 – 6737.
26) Gianguzza A., et al. Enhancement of Hydrolysis through the Formation of Mixed Heterometal Species:
Al3+/CH3Sn3+ Mixtures. J. Chem. Eng. Data 2013, 58, 821−826.
27) R. Zingales et al. Complex formation of the uranyl (UO22+) ion with the diethylene triamino pentaacetate
(DTPA) ligand at 25°C in 3 M sodium perchlorate. J. Chem. Eng. Data, 56 (2011) 2110-2118.
28) R. Zingales et al. Batch Experiments for the Determination of the Ti(IV,III) Couple Formal Potential in 1
mol·dm−3 HCl, 2 mol·dm−3 NaCl Medium at 25 °C J. Solution Chem. 38 (2009) 259-263
29) R. Zingales et al. Dioxouranium(VI) Hydrolysis at 75 and 100 °C in 3.6 mol·kg−1 LiClO4 Aqueous Medium .
J. Solution Chem. 37 (2008) 641-655
30) R. Zingales et al. The Formal Redox Potential of the Ti(IV, III) couple at 25°C in 1 M HCl 2 M NaCl
Medium. Ann. Chim. (Rome), 97 (2007) 713-721