Geology of Ore Deposits

, Volume 52, Issue 2, pp 167–178 | Cite as

Pressure-dependent stability of cadmium chloride complexes: Potentiometric measurements at 1–1000 bar and 25°C



Potentiometric measurements were performed in the Cd(NO3)2-KCl-H2O system at 25°C and 1–1000 bar using an isothermal cell with a liquid junction and equipped with a solid contact Cd-selective electrode. At 1 bar, the stepwise equilibrium constant of the fourth cadmium chloride complex CdCl 4 2− has been determined (log K 4 0 = −0.88 ± 0.25). The pressure-dependent stability constants for all cadmium chloride complexes have been experimentally established for the first time. As pressure increases from 1 to 1000 bar, the stability constants for the first, third, and fourth complexes change by less than 0.05 logarithmic units, whereas that for the second complex decreases by 0.33 logarithmic units. On the basis of these data, the partial molar volumes of four cadmium chloride complexes have been determined under standard state conditions: V 0(CdCl+) = 2.20 ± 3, V 0(CdCl2 (aq)) = 42.21 ± 5, V 0(CdCl 3 ) = 63.47 ± 10, and V 0(CdCl 4 2− ) = 81.35 ± 15 cm3mol−1. The linear correlation between the nonsolvation contributions of molar volumes and the number of ligands corresponds to the change in coordination from octahedral in Cd2+ and CdCl+ to tetrahedral in CdCl2 (aq), CdCl 3 , and CdCl 4 2− complexes. Using theoretical correlations, the HKF parameters allowing calculation of the volumetric properties of cadmium chloride complexes in a wide range of temperature and pressure have been obtained. The pressure effect on cadmium concentration in sphalerite in equilibrium with the H2O-NaCl hydrothermal fluid has been estimated. It is shown that the Cd content in sphalerite increases with pressure.


CdCl Molar Volume Hydrothermal Fluid Partial Molar Volume Chloride Complex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    D. Archer, “Thermodynamic Properties of Import to Environmental Processes and Remediation. I. Previous Thermodynamic Property Values for Cadmium and Some of Its Compounds,” J. Phys. Chem. Ref. Data. 27, 915–46 (1988).CrossRefGoogle Scholar
  2. 2.
    S. Arhland, “Complex Formation in Protic and Aprotic Media,” Pure Appl. Chem. 51, 2019–2039 (1979).CrossRefGoogle Scholar
  3. 3.
    H. L. Barnes, “Solubilities of Ore Minerals,” in Geochemistry of Hydrothermal Ore Deposits (Wiley, New York, 1979, pp. 404–460; Mir, Moscow, 1982, pp. 328-369).Google Scholar
  4. 4.
    E. W. Baumann, “Sensitivity of the Fluoride-Selective Electrode Below Micromolar Range,” Analyt. Chim. Acta. 54, 189–197 (1971).CrossRefGoogle Scholar
  5. 5.
    W. L. Bourcier and H. L. Barnes, “Ore Solution Chemistry-VII. Stabilities of Chloride and Bisulfide Complexes of Zinc to 350°C,” Econ. Geol. 82, 1839–1863 (1987).CrossRefGoogle Scholar
  6. 6.
    R. Caminiti, G. Licheri, G. Paschina et al., “X-ray Diffraction and Structural Properties of Aqueous Solutions of Divalent Metal-Chlorides,” Z. Naturforsch. 35a 1361-1367(1980).Google Scholar
  7. 7.
    V. P. Glushko, V. A. Medvedev, G. A. Bergman, et al., Thermodynamic Costants of Matter (VINITI, Moscow, 1972), Vol. 1 [in Russian].Google Scholar
  8. 8.
    V. M. Goldschmidt, Geochemistry (Oxford University Press, London, 1958).Google Scholar
  9. 9.
    W. Gottesmann and A. Kampe, “Zn/Cd Ratios in Calsilicate-Hosted Sphalerite Ores at Tumurtijn-ovoo, Mongolia,” Chem. Erde 67, 323–328 (2007).CrossRefGoogle Scholar
  10. 10.
    D. V. Grichuk, “The Cd/Zn Ratio As an Indicator of Contribution of Magmatic Fluids to Hydrorothermal Systems” in New Ideas in Geoscience (KDU, Moscow, 2005), Vol. 2, p. 83 [in Russian].Google Scholar
  11. 11.
    H. C. Helgeson, D. H. Kirkham and G. C. Flowers, “Theoretical Prediction of the Thermodynamic Behaviour of Aqueous Electrolytes at High Pressures and Temperatures: IV. Calculation of Activity Coefficients, Osmotic Coefficients, and Apparent Molal and Standard and Relative Partial Molal Properties to 600°C and 5 kbar,” Amer. J. Sci. 281. 1249-1561(1981).Google Scholar
  12. 12.
    J. J. Hemley, G. Cygan, J. B. Fein, et al., “Hydrothermal Ore-Forming Processes in the Light of Studies in Rock-Buffered Systems,” Econ. Geol. 87, 1–43 (1992).CrossRefGoogle Scholar
  13. 13.
    J. K. Hovey, Thermodynamics of Aqueous Solutions, PhD Thesis (Univ. of Alberta, Edmonton, Canada, 1988).Google Scholar
  14. 14.
    V. V. Ivanov, Environmental Geochemistry of Elements. Vol. 5: Rare d-Elements (Ekologiya, Moscow, 1997) [in Russian].Google Scholar
  15. 15.
    J. W. Johnson, E. H. Oelkers, and H.C. Helgeson, “SUPCRT92: a Software Package for Calculating the Standard Molal Thermodynamic Properties of Minerals, Gases, Aqueous Species, and Reactions from 1 to 5000 bar and 0 to 1000°C,” Comput. Geosci. 18, 899–947 (1992).CrossRefGoogle Scholar
  16. 16.
    I. R. Jonasson and D. F. Sangster, “Zn:Cd Ratios for Sphalerites Separated from Some Canadian Sulphide Ore Samples,” Geol. Surv. Can. Paper 78(1), 195–201, (1978).Google Scholar
  17. 17.
    D. R. Lide, Handbook of Geochemistry and Physics (CRS Press, Boca Raton, 2004).Google Scholar
  18. 18.
    A. B. Makeev, Isomorphism of Cadmium and Manganese in Sphalerite (Nauka, Leningrad, 1985) [in Russian].Google Scholar
  19. 19.
    E. Martell and R.M. Smith, Critically Selected Stability Constants of Metal Complexes, NIST Standard Reference Database 46, Version 5.0 (NIST, Gaithersburg, 1998), MD 20899.Google Scholar
  20. 20.
    J. F. W. Mosselmans, P. F. Schofield, J. M. Charnock, et al., “X-ray Absorption Studies of Metal Complexes in Aqueous Solution at Elevated Temperatures,” Chem. Geol. 127, 339–350 (1996).CrossRefGoogle Scholar
  21. 21.
    E. H. Oelkers and H. C. Helgeson, “Triple-Ion Anions and Polynuclear Complexing in Supercritical Electrolyte Solutions,” Geochim. Cosmochim. Acta. 54, 727–738 (1990).CrossRefGoogle Scholar
  22. 22.
    D. A. Palmer, H. R. Corti, A. Groteword, and K. E. Hyde, “Potentiometric Measurements of the Thermodynamics of Cadmium(II) Chloride Complexes to High Temperatures,” in Proceedings of the 13th International Conference on the Properties of Water and Steam (NRC Research Press, Ottawa, 2000), pp. 736–743.Google Scholar
  23. 23.
    G. Paschina, G. Piccaluga, G. Pinna, and M. Magini, “Chloro-Complexes Formation in ZnCl2 CdCl2 Aqueous Solutions: an X-Ray Diffraction Study,” J. Chem. Phys. 78, 5745–5749 (1983).CrossRefGoogle Scholar
  24. 24.
    P. J. Reilly and R. H. Stokes, “The Activity Coefficients of Cadmium Chloride in Water and Sodium Chloride Solutions at 25°C,” Austr. J. Chem. 23, 1397–405 (1970).Google Scholar
  25. 25.
    R. A. Robie and B. S. Hemingway, “Thermodynamic Properties of Minerals and Related Substances at 298.15 and 1 bar (105 Pascals) Pressure and at High Temperatures,” US Geol. Surv. Bull. 2131 (1995).Google Scholar
  26. 26.
    D. V. Rozhkova, A. V. Zotov, and E. F. Bazarkina, “The Detection Limit of Ion-Selective Electrodes in the Pres ence of Complexing Ligand, a Case of Fluorine-Selective Electrode,” in New Ideas in Geosciences (RGGRU, Moscow, 2009), Vol. 3, p. 286 [in Russian].Google Scholar
  27. 27.
    J. R. Ruaya, and T. M. Seward, “The Stability of Chloro-Zinc (II) Complexes in Hydrothermal Solutions up to 350°C,” Geochim. Cosmochim. Acta. 50, 651–662 (1986).CrossRefGoogle Scholar
  28. 28.
    B. N. Ryzhenko and O. V. Bryzgalin, “Electrolytic Dissociation of Acids under Conditions of Hydrothehrmal Process,” Geokhimiya 25(1), 137–142 (1987).Google Scholar
  29. 29.
    T. M. Seward and T. Driesner, “Hydrothermal Solution Structure: Experiments and Computer Simulations,” in Aqueous Systems at Elevated Temperatures and Pressures: Physical Chemistry in Water, Steam and Hydrothermal Solutions (Academic Press, London, 2004), pp. 149–182.CrossRefGoogle Scholar
  30. 30.
    J. A. Sharps, G.E. Brown Jr., and J. F. Stebbins, “Kinetics and Mechanism of Ligand Exchange of Au(III), Zn(II), and Cd(II) Chlorides in Aqueous Solutions: an NMR Study from 28-98°C,” Geochim. Cosmochim. Acta. 57, 721–731 (1993).CrossRefGoogle Scholar
  31. 31.
    E. L. Shock and H. C. Helgeson, “Calculation of the Thermodynamic and Transport Properties of Aqueous Species at High Pressures and Temperatures: Correlation Algorithms for Ionic Species and Equation of State Prediction to 5 kb and 1000°C,” Geochim. Cosmochim. Acta. 52, 2009–2036 (1988).CrossRefGoogle Scholar
  32. 32.
    E. L. Shock, H. C. Helgeson, and D. A. Sverjensky, “Calculation of the Thermodynamic and Transport Properties of Aqueous Species at High Pressures and Temperatures: Standard Partial Molal Properties of Inorganic Neutral Species,” Geochim. Cosmochim. Acta 53, 2157–2183 (1989).CrossRefGoogle Scholar
  33. 33.
    E. L. Shock, D. C. Sassani, M. Willis, and D. A. Sverjensky, “Inorganic Species in Geologic Fluids: Correlations Among Standard Molal Thermodynamic Properties of Aqueous Ions and Hydroxide Complexes,” Geochim. Cosmochim. Acta 61, 907–950 (1997).CrossRefGoogle Scholar
  34. 34.
    Yu. S. Shvarov and E.N. Bastrakov, HCh: a Software Package for Geochemical Equilibrium modeling. User’s Guide (Australian Geological Survey Organization, Canberra, 1999), Record 199/25Google Scholar
  35. 35.
    Yu. S. Shvarov, “HSh: New Potentialities for Thermodynamic Simulation of Geochemical Systems Offered by Windows,” Geokhimiya 46(8), 834–839 (2008) [Geochem. Int. 46 (8), 834–829 (2008)].Google Scholar
  36. 36.
    A. P. Solovov, A. Ya. Arkhipov, V. A. Bugrov, et al., Handbook for Geochemical Exploration of Mineral Resources (Nedra, Moscow, 1990) [in Russian].Google Scholar
  37. 37.
    D. A. Sverjensky, E. L. Shock, and H. C. Helgeson, “Prediction of the Thermodynamic Properties of Aqueous Metal Complexes to 1000°C and 5 kb,” Geochim. Cosmochim. Acta 61, 1359–1412 (1997).CrossRefGoogle Scholar
  38. 38.
    T. W. Swaddle and M. S. Mak, “The Partial Molar Volumes of Aqueous Metal Cations: Their Prediction and Relation to Volumes of Activation for Water Exchange,” Canad. J. Chem. 61, 473–480 (1983).CrossRefGoogle Scholar
  39. 39.
    J. C. Tanger and H. C. Helgeson, “Calculation of the Thermodynamic and Transport Properties of Aqueous Species at High Pressures and Temperatures: Revised Equation of State for the Standard Partial Properties of Ions and Electrolytes,” Amer. J. Sci. 288, 19–98 (1988).Google Scholar
  40. 40.
    V. L. Tauson and L. V. Chernyshev, “Investigation of Phase Relations and Structural Features of Mixed Crystals in the ZnS-CdS System,” Geokhimiya 15(9), 1299–1311 (1977).Google Scholar
  41. 41.
    C. E. Vanderzee and H. J. Dawson, “The Stability Constants of Cadmium Chloride Complexes: Variation with Temperature and Ionic Strength,” J. Amer. Chem. Soc. 75, 5659–5663 (1953).CrossRefGoogle Scholar
  42. 42.
    K. Von Damm, “Seafloor Hydrothermal Activity: Black Smoker Chemistry and Chimneys,” Ann. Rev. Earth and Planet. Sci. Lett. 18, 173–204 (1990).CrossRefGoogle Scholar
  43. 43.
    S. Xuexin, “Minor Elements and Ore Genesis of the Fankou Lead-Zinc Deposits, China,” Mineral. Deposita 19, 95–104 (1984).CrossRefGoogle Scholar
  44. 44.
    A. V. Zotov, L. A. Koroleva, and E. G. Osadchii, “Potentiometric Study of the Stability of Eu3+ Acetate Complex as a Function of Pressure (1–1000 bar) at 25°C,” Geokhimiya 44(4), 384–394 (2006) [Geochem. Int 44 (4), 384–394].Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2010

Authors and Affiliations

  • E. F. Bazarkina
    • 1
  • A. V. Zotov
    • 1
  • N. N. Akinfiev
    • 1
  1. 1.Institute of Geology of Ore Deposits, Petrography, Mineralogy, and GeochemistryRussian Academy of SciencesMoscowRussia

Personalised recommendations