Evaluation of the Standard Thermodynamic Functions of Hydrate Sulfates of Divalent Metals (Ca, Mn, Cd, Fe, Zn, Cu, Mg, Ni, Co, and Be)

• Published in: Geochemistry international 2022-10, Vol.60 (10), p.981-994
• Main Authors: Rusal, O. S., Eremin, O. V.
• Format: Article
• Language: English
• Subjects: Analysis; Beryllium; Cadmium; Calcium; Cations; Cobalt; Copper; Correlation analysis; Crystallization; Crystallography; Earth and Environmental Science; Earth Sciences; Enthalpy; Geochemistry; Hydrates; Iron; Least squares method; Magnesium; Manganese; Mathematical analysis; Metals; Nickel; Salts; Sulfates; Sulphates; Thermal properties; Thermodynamic equilibrium; Thermodynamic properties; Thermodynamics; Zinc
• ISSN: 0016-7029; 1556-1968
• DOI: 10.1134/S001670292210007X

— Based on the known thermodynamic characteristics, changes in the standard Gibbs energies Δ ƒ G ° and enthalpies Δ ƒ H ° of formation, standard values of entropies S ° at a temperature of 298.15 K of hydrate sulfates of divalent metals (Ca, Mn, Cd, Fe, Zn, Cu, Mg, Ni, Co, and Be), equations of linear dependences of the values of the thermodynamic functions of the compounds on the content of crystallization water were obtained using the least squares method. Comparison of the estimates with the multidimensional correlation analysis method shows a higher accuracy of calculations with the considered approach. A correlation has been revealed between the thermodynamic properties of the hydrates and the crystallographic radii of the cations. The derived equations are used to calculate unknown properties of some hydrates. Comparison of the calculations of the thermodynamic equilibria of the MeSO 4 –H 2 O systems by the Selector PC showed a good agreement with the experimental diagrams of the solubility of salts in water.