Osmotic and Activity Coefficients of the {xZnCl2+(1−x)ZnSO4}(aq) System at 298.15 K

Abstract

Isopiestic vapor pressure measurements were made for {xZnCl 2 + (1 -

Calculation of equilibrium stable isotope partition function ratios for aqueous zinc complexes and metallic zinc

“…Calculated concentrations of zinc species in typical electroplating solutions are shown in Fig. 2B-D, where a Pitzer model for the activity of the ½ZnSO 4 0 ðaqÞ complex that forms in H 2 SO 4 was used (Ninkovic et al, 2007). The choice of activity model is important in modeling contact ion-pairing of neutral complexes such as ZnSO 4 in concentrated solutions (ionic strength >0.5 M), as demonstrated by the range of estimated stability constants for the ZnSO 4 formation reaction reported in the literature (log K = 2.05-2.52, (Wasylkiewicz, 1990)).…”

“…Organic complexes of zinc also play an important role in biological cycles, with zinc forming the active site of biologically essential enzymes such as carbonic anhydrases (Moroney et al, 2001). Theoretical and experimental studies have focused on the structure and stability of aqueous zinc species to determine the nature of the first and second shell solvated structures (Albright et al, 2000;Pye et al, 2006;Ninkovic et al, 2007;Rudolph and Pye, 1999a;Rudolph et al, 1999a,b). Rudolph and Pye (1999b) used ab initio methods to determine the optimal first-and second-shell solvation geometries of Zn 2+ , showing that an octahedrally coordinated first shell of six waters is bound to the zinc via the oxygen atoms.…”

Effect of temperature and mass transport on transition metal isotope fractionation during electroplating

“…The speciation in iron sulfate solutions (Parkhurst, 1995) is a little more complex with a mixture of species forming: ½FeðH 2 O 6 Þ 2þ ðaqÞ (36.7%), ½FeSO 4 0 ðaqÞ (50.8%) and ½FeHSO 4 þ ðaqÞ (12.5%) at a pH of 1.6. In the case of Zn, thermodynamic models (Parkhurst, 1995;Liu et al, 2007;Ninkovic et al, 2007) of Zn speciation show that the ½ZnSO 4 0 ðaqÞ complex is predominant in the bulk solution of the sulfate experiments (Zn Exp. 01 and Zn Exp.…”

Osmotic Coefficients of Electrolyte Solutions

“…It is easily seen from eq 9 that m → 0 gives γ obs ≈ α f γ, whereas m ≥ m 0 gives γ obs ≈ γ, according to eq 7. For H 2 SO 4 , the experimental value of c lim = 8.78 M has been used corresponding to m 0 = 5.4 m ; for ZnSO 4 , the theoretical value c lim = 7.4 M has been used in place of 8 M as reported in ref , according to recently revised experimental data concerning this metal sulfate. , To evaluate c lim for ZnSO 4 , calculated γ have been fitted to experimental ones so as to have the very same trend at the highest available concentrations (near saturation). For ZnSO 4 , the theoretical m 0 is 3.95 m.…”

“…The formation of ion pairs in metal sulfates at very dilute solutions is a debated point in literature. ,,,, An objection is that experimental K A values are too largely depending on the measurement method, e.g., for ZnSO 4 , K A values range from 111 to 309 about . Another objection derives from the fact that, by means of suitable shape-based parameters in the Pitzer theory, it is possible to calculate γ and φ without considering ion association at strong dilutions. ,, However, as outlined in ref , calculations of the excess free energies from both association- and non-association-based theories are not conclusive at present; that legitimates also the conclusions of the pseudolattice model.…”