Thermochemical Studies on Metal Complexes. IX. Free Enerrgy, Enthalpy, and Entropy Changes for Stepwise Formation of Zinc(II) Halide Complexes in Aqueous Solution.

Gerding, Per; Dahlén, Birgitta; Seip, H. M.; Holme, Tord; Lindberg, Alf A.; Jansen, Gert; Lamm, Bo; Samuelsson, Benny

doi:10.3891/acta.chem.scand.23-1695

Cited by 28 publications

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“…There are numerous data published for zinc chloride complexes at 25øC resulting from a variety of methods of study including: potentiometric techniques (Sill(•n and Liljeqvist, 1944; Fedorov et al, 1970;Skou et al, 1977), anion exchange (Kraus and (Gerding, 1969), nuclear magnetic resonance (Marciel et al, 1977), and numerous Raman studies (Irish et al, 1963;Morris et al, 1963;Quicksall and Spiro, 1966;Gilbert, 1967;Schulz, 1974), as well as a synthesis of several of these techniques in Giaquinta et al (1983). Zinc chloride complexes clearly exist at low temperatures, but in spite of the numerous studies, their stoichiometries and stabilities are still uncertain.…”

Section: Zinc Chloride Complexes--published Resultsmentioning

confidence: 98%

“…It is noteworthy that this effect was present even at temperatures as high as 300øC. KI was chosen as a background electrolyte because complex formation between Zn +• and I-is known to be very weak (Gerding, 1969) and could therefore be ignored for the low KI concentrations of these solubility measurements. Other examples of the use of this technique to suppress colloid formation are discussed in Remy (1956).…”

Section: H2s(aq) = H + + Hs-mentioning

confidence: 99%

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Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Bourcier¹,

Barnes²

1987

Economic Geology

121

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The association constants for the dominant zinc chloride complexes were determined from solubility measurements of zincite (ZnO) and smithsonite (ZnCO3) in 0 to 5 m NaC1-CO2-H20 solutions from 100 ø to 350øC. For the important sphalerite solubility-controlling reactions: Zn +2 + CI-= ZnC1 +, Zn +• + 2C1-= ZnClø•, Zn +• + 3C1-= ZnCI•, Zn +• + 4C1---ZnCI• •, and ZnS(s) + 2H + --Zn +2 + H•S(aq), the respective logs of the equilibrium constants for temperatures (øC) equal to 100, 150, 200, 250, 300, and 350 are 1.2, 2., -1.7. The log K values for the last reaction were calculated here using free energy data for ZnS(s), Zn +•, and H•S(aq). The equilibrium constants for the dominant zinc bisulfide complexes were determined from solubility measurements of sphalerite (ZnS) in 0 to 4 m NaHS-H•S-H20 solutions from 100 ø to 350øC. The important solubility-controlling reactions are: ZnS(•) + H•O(t) = Zn(OH)(HS) ø, ZnS(,) + H2S(aq) --Zn(HS)•, ZnS(•) + H2S(aq) + HS-= Zn(HS)•, and ZnS(,) + H•S(aq) + 2HS-= Zn(HS)• •, and the respective logs of their equilibrium constants for temperatures (øC) equal to 100, 150,200,250, 300, and 350 areEnthalpies and entropies of complex formation derived from these data demonstrate the increasing importance of electrostatic effects in complex formation at higher temperatures. Good agreement was found between our measured and calculated solubilities of sphalerite from 100 ø to 350øC in an NaC1-H•S-H20 solution and in an NaC1-CaCI•-CO•-H•S-H•O solution in equilibrium with calcite. Therefore, the nine equilibrium constants provide confirmed resolution of sphalerite solubilities in ore solutions having chemistries quite different from those used in the solubility experiments. Sample calculations of sphalerite solubilities in Kuroko-type massive sulfide ore fluids are given which demonstrate the effectiveness of cooling in the temperature range of 250 ø to 300øC as a precipitation mechanism for sphalerite.

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Section: Zinc Chloride Complexes--published Resultsmentioning

confidence: 98%

Section: H2s(aq) = H + + Hs-mentioning

confidence: 99%

Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Bourcier¹,

Barnes²

1987

Economic Geology

121

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“…One calorimetric study on the formation of Zn II chlorido-complexes has been reported [69GEa]. The stepwise reaction enthalpies determined in 3 molؒdm -3 NaClO 4 solution at 25 °C were Δ r H(K 1 ) = 5.5 ± 0.1 kJؒmol -1 , Δ r H(K 2 ) = 38 ± 8 kJؒmol -1 , and Δ r H(K 3 ) = 0 ± 8 kJؒmol -1 .…”

Section: The Zn 2+ + CL -Systemmentioning

confidence: 99%

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)

Powell

Brown

Byrne

et al. 2013

Pure and Applied Chemistry

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Abstract:The numerical modeling of Zn II speciation amongst the environmental inorganic ligands Cl -, OH -, CO 3 2-, SO 4 2-, and PO 4 3-requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log 10 β p,q,r°v alid at I m = 0 molؒkg -1 and 25 °C (298.15 K), and reports the empirical reaction ion interaction coefficients, Δε, required to calculate log 10 β p,q,r values at higher ionic strengths using the Brønsted-Guggenheim-Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, Δ r H, are reported where available. There is scope for additional high-quality measurements for the Zn 2+ + H + + CO 3 2-system and for the Zn 2+ + OH -and Zn 2+ + SO 4 2-systems at I > 0. In acidic and weakly alkaline fresh water systems (pH < 8), in the absence of organic ligands (e.g., humic substances), Zn II speciation is dominated by Zn 2+ (aq). In this respect, Zn II contrasts with Cu II and Pb II (the subjects of earlier reviews in this series) for which carbonato-and hydroxido-complex formation become important at pH > 7. The speciation of Zn II is dominated by ZnCO 3 (aq) only at pH > 8.4.In seawater systems, the speciation at pH = 8.2 is dominated by Zn 2+ (aq) with ZnCl + , Zn(Cl) 2 (aq), ZnCO 3 (aq), and ZnSO 4 (aq) as minor species. This behaviour contrasts with that for Cu II and Pb II for which at the pH of seawater in equilibrium with the atmosphere at 25 °C (log 10 {[H + ]/c°} ≈ 8.2) the MCO 3 (aq) complex dominates over the MCl n (2-n)+ species. The lower stability of the different complexes of Zn II compared with those of Cu II , Pb II , and Cd II is also illustrated by the percentage of uncomplexed M 2+ in seawater, which is ca. 55, 3, 2, and 3.3 % of [M II ] T , respectively.

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“…Les complexes ~nC1;-, ZnC1; sont plus stables dans le sulfolane et le dim&thylsulfoxyde (16) (solvants aprotoniques) que dans le mCthanol(17) et l'eau (18), en raison des propriCtts peu solvatantes du sulfolane et du DMSO (tableau 1). Ces rCsultats sont en accord avec les hypothkses formulCes par Ahrland (19), relatives ti la solvatation des complexes mttalliques en milieux protoniques et aprotoniques.…”

Section: Constantes De Stabilite' Des Complexes Chlorozincates[ii]unclassified

Influence de nitrates métalliques sur l'équilibre de dissociation ionique: dans le sulfolane

Wartel¹,

Fischer²

1986

Can. J. Chem.

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Thermochemical Studies on Metal Complexes. IX. Free Enerrgy, Enthalpy, and Entropy Changes for Stepwise Formation of Zinc(II) Halide Complexes in Aqueous Solution.

Cited by 28 publications

References 0 publications

Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)

Influence de nitrates métalliques sur l'équilibre de dissociation ionique: dans le sulfolane

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Thermochemical Studies on Metal Complexes. IX. Free Enerrgy, Enthalpy, and Entropy Changes for Stepwise Formation of Zinc(II) Halide Complexes in Aqueous Solution.

Cited by 28 publications

References 0 publications

Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Ore solution chemistry; VII, Stabilities of chloride and bisulfide complexes of zinc to 350 degrees C

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn2+ + OH-, Cl-, CO3 2-, SO4 2-, and PO4 3- systems (IUPAC Technical Report)

Influence de nitrates métalliques sur l'équilibre de dissociation ionique: dans le sulfolane

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Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)