Abstract
The hydrolytic behavior of antimonic acid, Sb(OH) o5 , was experimentally investigated, at fixed temperatures within the range 10–40 °C, by both titration of dilute Na-antimonate solutions with HClO4 and single-point pH measurements of diluted Sb(OH) o5 solutions. The thermodynamic constants, K a, for the reaction:
were derived at different controlled temperatures, based on pH measurements, applying suitable mass and electrical balances and correcting the concentrations of ionic species for medium effects. From the resulting log 10 K a values, those of the corresponding isocoulombic equilibrium reaction:
were computed and used to derive its thermodynamic properties. These were finally combined with the corresponding thermodynamic properties of the water association reaction, to obtain robust estimations of ΔG or , ΔS or and ΔH or for the ionogenic reaction. These are the first thermodynamic data at temperatures different from 25 °C for the ionization reaction of Sb(OH) o5 . The results of the present work confirm that Sb(OH) o5 is a moderately weak and monoprotic acid with a pK a of 2.848 at 25 °C.
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Baes, C.F., Mesmer, R.E.: The Hydrolysis of Cations. Wiley, New York (1976)
Lefebvre, J., Maria, H.: Étude des équilibres dans les solutions récentes de polyantimoniates. C. R. Acad. Sci. Paris 256, 3121–3124 (1963)
Pauling, L.: The formulas of antimonic acid and the antimonates. J. Am. Chem. Soc. 55, 1895–1900 (1933)
Gayer, K.H., Garrett, A.B.: The equilibria of antimonious oxide (rhombic) in dilute solutions of hydrochloric acid and sodium hydroxide at 25 °C. J. Am. Chem. Soc. 74, 2353–2354 (1952)
Mishra, S.K., Gupta, Y.K.: Spectrophotometric study of the hydrolytic equilibrium of Sb(III) in aqueous perchloric acid solution. Indian J. Chem. 6, 757–758 (1968)
Ahrland, S., Bovin, J.: The complex formation of antimony(III) in perchloric acid and nitric acid solutions. A solubility study. Acta Chem. Scand. A 28, 1089–1100 (1974)
Vasil’ev, V.P., Shorokhova, V.I.: Determination of the standard thermodynamic characteristics of the antimonyl ion SbO+ and antimony oxide by a potentiometric method. Electrokhimiya 8, 185–190 (1972)
Vasil’ev, V.P., Shorokhova, V.I.: Determination of the thermodynamic characteristics of antimony(III) in alkaline solutions by a solubility method. Russ. J. Inorg. Chem. 18, 161–164 (1973)
Popova, M.Ya., Khodakovsky, I.L., Ozerova, N.A.: Experimental determination of the thermodynamic properties of hydroxo- and hydroxofluoride complexes of antimony at temperatures up to 200 °C. Geokhimiya 6, 835–843 (1975)
Zotov, A.V., Shikina, N.D., Akinfiev, N.N.: Thermodynamic properties of the Sb(III) hydroxide complex Sb(OH)3(aq) at hydrothermal conditions. Geochim. Cosmochim. Acta 67, 1821–1836 (2003)
Zakaznova-Herzog, V.P., Seward, T.M.: Antimonous acid protonation/deprotonation equilibria in hydrothermal solutions to 300 °C. Geochim. Cosmochim. Acta 70, 2298–2310 (2006)
Smith, R.M., Martell, A.E.: Critical Stability Constants, vol. 4: Inorganic Complexes. Plenum, New York (1976)
Lothenbach, B., Ochs, M., Wanner, H., Yui, M.: Thermodynamic data for the speciation and solubility of Pd, Pb, Sn, Sb, Nb and Bi in aqueous solution. JNC Report TN8400 99-011 (1999)
Filella, M., May, P.M.: Computer simulation of the low-molecular-weight inorganic species distribution of antimony(III) and antimony(V) in natural waters. Geochim. Cosmochim. Acta 67, 4013–4031 (2003)
Nekrassov, B.: Chimie Minérale. Ed. de Moscou, Moscow (1969)
Silvestroni, P.: Fondamenti di Chimica. Masson, Milano (1997)
Slade, R.C.T., Gillian, P.H., Ramanan, A., Prince, E.: Structure and proton conduction in pyrochlore-type antimonic acid: a neutron diffraction study. Solid State Ion. 92, 171–181 (1996)
England, W.A., Cross, M.G., Hamnett, A., Wiseman, P.J., Goodenough, J.B.: Fast proton conduction in inorganic ion-exchange compounds. Solid State Ion. 1, 231–249 (1980)
Jain, D.V.S., Banerjee, A.K.: On the structure of antimonates. J. Inorg. Nucl. Chem. 19, 177–179 (1961)
Gate, S.H., Richardson, E.: Some studies on antimonic acid. I. Some properties, effect of H2O2, and reaction with polyhydroxy compounds. J. Inorg. Nucl. Chem. 23, 257–263 (1961)
King, E.J.: Acid-base equilibria. In: Topics 15: Equilibrium Properties of Electrolyte Solutions. The International Encyclopedia of Physical Chemistry and Chemical Physics, vol. 4. Pergamon, New York (1965)
Davison, W., Woof, C.: Performance tests for the measurement of pH with glass electrodes in low ionic strength solutions including natural waters. Anal. Chem. 57, 2567–2570 (1985)
Cheng, K.L., Zhu, D.-M.: On calibration of pH meters. Sensors 5, 209–219 (2005)
Abe, M., Ito, T.: Synthetic inorganic ion-exchange materials. X. Preparation and properties of so-called antimonic(V) acid. Bull. Chem. Soc. Jpn. 41, 333–342 (1968)
Willis, S.B., Neumann, H.M.: Hydrolysis and nucleophilic substitution of the hexachloro-antimonate(V) ion in the pH range 2–12. J. Am. Chem. Soc. 91, 2924–2928 (1969)
Matsuo, T., Kobayashi, K., Tago, K.: Estimation of the solubility dependence of aluminate salts of alkali metals on ion radii of alkali metals by LDF molecular orbital calculations. J. Phys. Chem. 100, 6531–6542 (1996)
Travers, J.G., McCurdy, K.G., Dolman, D., Hepler, L.G.: Glass-electrode measurements over a wide range of temperatures: the ionization constants (5–90 °C) and thermodynamics of ionization of aqueous benzoic acid. J. Solution Chem. 4, 267–274 (1975)
Martell, A.E., Hancock, R.D.: Metal Complexes in Aqueous Solutions. Plenum, New York (1996), 253 pp
Bates, R.G.: Determination of pH: Theory and Practice, 2nd edn. Wiley, New York (1973)
Helgeson, H.C., Kirkham, D.H.: Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures, I: summary of the thermodynamic/electrostatic properties of the solvent. Am. J. Sci. 274, 1089–1198 (1974)
Knauss, K.G., Wolery, T.J., Jackson, K.J.: Reply to comment by R.E. Mesmer on “A new approach to measuring pH in brines and other concentrated electrolytes”. Geochim. Cosmochim. Acta 55, 1177–1179 (1991)
Wolery, T.W., Jarek, R.L.: Software user’s manual. EQ3/6, Version 8.0. Sandia National Laboratories, U.S. Dept. of Energy Report (2003)
Lindsay, W.T. Jr.: Estimation of concentration quotients for ionic equilibria in high temperature water: the model substance approach. In: 41st Int. Water Conf. pp. 284–294 (1980)
Johnson, J.W., Oelkers, E.H., Helgeson, H.C.: SUPCRT 92: A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 to 5000 bars and 0 to 1000 °C. Comput. Geosci. 18, 899–947 (1992)
Shock, E.L., Helgeson, H.C.: Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: correlation algorithms for ionic species and equation of state predictions to 5 kb and 1000 C. Geochim. Cosmochim. Acta 52, 2009–2036 (1988)
Shock, E.L., Helgeson, H.C., Sverjensky, D.A.: 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)
Shock, E.L., Sassani, D.C., Willis, M., Sverjensky, D.A.: Inorganic species in geologic fluids: correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes. Geochim. Cosmochim. Acta 61, 907–950 (1997)
Pokrovski, G., Gout, R., Schott, J., Zotov, A., Harrichoury, J.-C.: Thermodynamic properties and stoichiometry of As(III) hydroxide complexes at hydrothermal conditions. Geochim. Cosmochim. Acta 60, 737–749 (1996)
Pokrovski, G., Zakirov, I., Roux, J., Testemale, D., Hazemann, J.-L., Bychkov, A.Y., Golikova, G.V.: Experimental study of arsenic speciation in vapor phase to 500 °C: implications for As transport and fractionation in low-density crustal fluids and volcanic gases. Geochim. Cosmochim. Acta 66, 3453–3480 (2002)
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Accornero, M., Marini, L. & Lelli, M. The Dissociation Constant of Antimonic Acid at 10–40 °C. J Solution Chem 37, 785–800 (2008). https://doi.org/10.1007/s10953-008-9280-4
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DOI: https://doi.org/10.1007/s10953-008-9280-4