Advertisement

Journal of Thermal Analysis and Calorimetry

, Volume 112, Issue 1, pp 95–102 | Cite as

Thermodynamic characterization of chromium tellurate

  • Rimpi Dawar
  • R. Pankajavalli
  • J. Joseph
  • S. Anthonysamy
  • V. Ganesan
Article

Abstract

The standard Gibbs energy of formation of chromium tellurate, Cr2TeO6 was determined from the vapour pressure measurement of TeO2(g) over the phase mixture Cr2TeO6(s) + Cr2O3(s) in the temperature range 1,183–1,293 K. A thermogravimetry (TG)-based transpiration technique was used for the vapour pressure measurement. This technique was validated by measuring the vapour pressure of CdCl2(g) over CdCl2(s). The temperature dependence of the vapour pressure of CdCl2(g) could be represented as logp (Pa) (±0.02) = 12.06 − 8616.3/T (K) (734 − 823 K). A ‘third-law’ analysis of the vapour pressure data yielded a mean value of 185.1 ± 0.4 kJ mol−1 for the enthalpy of sublimation of CdCl2(s). The temperature dependence of vapour pressure of TeO2(g) generated by the incongruent vapourisation reaction, \( {\text{Cr}}_{ 2} {\text{TeO}}_{ 6} (\rm s) \to {\text{Cr}}_{ 2} {\text{O}}_{ 3} (\rm s) + {\text{TeO}}_{ 2} (\rm g) + 1/2\,{\text{O}}_{ 2} (\rm g) \) could be represented as logp (Pa) (±0.04) = 18.57 – 21,199/T (K) (1,183 – 1,293 K). The temperature dependence of the Gibbs energy of formation of Cr2TeO6 could be expressed as \( \{ \Updelta G_{\text{f}}^{ \circ } ({\text{Cr}}_{ 2} {\text{TeO}}_{ 6} ,{\text{ s}}){\text{ (kJ}}\,{\text{mol}}^{ - 1} )\pm 4. 0 {\text{\} = }} - 1 6 2 5. 6 { \,+\, 0} . 5 3 3 6\,T({\text{K}}) \, (1{,}183 - 1{,}293\,{\text{K}}). \) A drop calorimeter was used for measuring the enthalpy increments of Cr2TeO6 in the temperature range 373–973 K. Thermodynamic functions viz., heat capacity, entropy and Gibbs energy functions of Cr2TeO6 were derived from the experimentally measured enthalpy increment values. \( \Updelta H_{{{\text{f}},298\,{\text{K}}}}^{ \circ } ({\text{Cr}}_{ 2} {\text{TeO}}_{ 6} ) \) was found to be −1636.9 ± 0.8 kJ mol−1.

Keywords

Chromium tellurate Transpiration Gibbs energy of formation Drop calorimeter Enthalpy increment 

Notes

Acknowledgements

The authors express their sincere gratitude to Dr. R. Babu, Dr. R. Asuvathraman and Dr. M. V. Krishniah for their useful suggestions during this study.

References

  1. 1.
    Kleykamp H. Chemical states of the fission products in oxide fuels. J Nucl Mater. 1985;131:221–46.CrossRefGoogle Scholar
  2. 2.
    Adamson MG, Aitken EA, Lindemer TB. Chemical thermodynamics of Cs and Te fission product interactions in irradiated LMFBR mixed-oxide fuel pins. J Nucl Mater. 1985;130:375–92.CrossRefGoogle Scholar
  3. 3.
    Chattopadhyay G, Juneja JM. A thermodynamic database for tellurium bearing systems relevant to nuclear technology. J Nucl Mater. 1993;202:10–28.CrossRefGoogle Scholar
  4. 4.
    Cordfunke EHP, Konings RJM. Chemical interaction in water cooled nuclear fuel: a thermochemical approach. J Nucl Mater. 1988;152:301–9.CrossRefGoogle Scholar
  5. 5.
    Krishnan K, Rama Rao GA, Venugopal V. Structural and thermochemical studies on Cr2TeO6 and Fe2TeO6. J Alloys Compd. 2001;316:264–8.CrossRefGoogle Scholar
  6. 6.
    Gospodinov G, Atanasova L. Specific thermal and thermodynamic properties of the tellurites Fe2(TeO3)3, Fe2TeO5 and Fe2Te4O11. J Therm Anal Calorim. 2008;91:655–7.CrossRefGoogle Scholar
  7. 7.
    Ali Basu M, Mishra R, Kerkar AS, Bharadwaj SR, Das D. Gibbs energy of formation of solid Ni3TeO6 from transpiration studies. J Nucl Mater. 2002;301:183–6.CrossRefGoogle Scholar
  8. 8.
    Krishnan K, Rama Rao GA, Mudhler KDS, Venugopal V. Vaporization behavior and Gibbs energy of formation of Ni2Te3O8, NiTe2O5 and Ni3TeO6. J Alloys Compd. 1999;288:96–101.CrossRefGoogle Scholar
  9. 9.
    Khadilkar HV, Bhojane SM, Kulkarni J, Kulkarni SG. Thermal properties of Na2TeO4(s) and TiTe3O8(s). J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2332-4.
  10. 10.
    Preston-Thomas H. The international temperature scale of 1990 (ITS-90). Metrologia. 1990;27(1):3–10.CrossRefGoogle Scholar
  11. 11.
    Krishniah MV. Study of thermophysical properties of some materials of interest in nuclear technology. Ph.D. Thesis, University of Madras. 2000.Google Scholar
  12. 12.
    Anthonysamy S, Joseph J, Vasudeva Rao PR. Calorimetric studies on urania-thoria solid solutions. J Alloys Compd. 2000;299:112–7.CrossRefGoogle Scholar
  13. 13.
    Synthetic Sapphire Al2O3, Certificate of Standard Reference Materials, SRM 720, 1982. (National Bureau of Standards, U.S. Department of Commerce, Washington, DC 20234, USA).Google Scholar
  14. 14.
    Moss HI. Ph.D. Thesis, Indiana University. 1961.Google Scholar
  15. 15.
    Keneshea FJ, Cubicciotti DD. Vapour pressure of cadmium chloride and thermodynamic data for CdCl2 gas. J Chem Phys. 1964;40:1778–9.CrossRefGoogle Scholar
  16. 16.
    Skudlarski K, Dudek J, Kapala J. Thermodynamics of sublimation of cadmium halides investigated by the mass-spectrometric method. J Chem Thermodyn. 1987;19:857–62.CrossRefGoogle Scholar
  17. 17.
    Barton JL, Bloom H. A boiling point method for determination of vapour pressures of molten salts. J Phys Chem. 1956;60:1413–6.CrossRefGoogle Scholar
  18. 18.
    Bloom H, Welch BJ. The vapour pressure of cadmium and zinc chlorides. J Phys Chem. 1958;62:1594–5.CrossRefGoogle Scholar
  19. 19.
    Niwa K. Determination of the vapour pressure of solid salts. J Fac Sci Hakkaido Univ Ser III. 1940;3:17–61.Google Scholar
  20. 20.
    Topor L. Thermodynamic study of alkali metal vapours in equilibrium with the liquid phase. J Chem Thermodyn. 1972;4:739–44.CrossRefGoogle Scholar
  21. 21.
    Knacke O, Kubaschewski O, Hesselmann K. Thermochemical properties of inorganic substances. 2nd ed. Berlin: Springer; 1991.Google Scholar
  22. 22.
    Cristol B, Houriez J, Balesdent D. Détermination par ébullition isobare de la pression de vapeur de CdCl2 pur et du mélange binaire fondu CdCl2-KCl. J Less-Common Met. 1985;113:43–57.CrossRefGoogle Scholar
  23. 23.
    Dharwadkar SD, Kerkar AS, Samant MS. A microthermogravimetric system for the measurement of vapour pressure by a transpiration method. Thermochim Acta. 1993;217:175–86.CrossRefGoogle Scholar
  24. 24.
    Muenow DW, Hastie JW, Hauge R, Bautista R, Margrave JL. Vapourization, thermodynamics and structures of species in the tellurium + oxygen system. Trans Faraday Soc. 1969;65:3210–20.CrossRefGoogle Scholar
  25. 25.
    Balakrishnan S, Pankajavalli R, Anthonysamy S, Ananthasivan K. Thermodynamic stability of Sm2TeO6. Thermochim Acta. 2008;467:80–5.CrossRefGoogle Scholar
  26. 26.
    Aggarwal R, Singh Z. Enthalpy increments of Ba2Te3O8(s) and Ba3Te2O9(s) compounds. J Alloys Compd. 2006;414:230–4.CrossRefGoogle Scholar
  27. 27.
    Lindemer TB, Bessman TM. Thermodynamic review and calculations—alkali-metal oxide systems with nuclear fuels, fission products, and structural materials. J Nucl Mater. 1981;100:178–226.CrossRefGoogle Scholar
  28. 28.
    Pankajavalli R, Jain A, Babu R, Anthonysamy S, Ananthasivan K, Ganesan V, Nagarajan K. Thermodynamic studies on Pr2TeO6. J Therm Anal Calorim. 2012;. doi: 10.1007/s10973-012-2461-9.Google Scholar
  29. 29.
    Atanasova L, Dimitrova GB. Heat capacity and thermodynamic properties of tellurites Yb2(TeO3)3, Dy2(TeO3)3 and Er2(TeO3)3. J Therm Anal Calorim. 2012;107:809–12.CrossRefGoogle Scholar
  30. 30.
    Hultgren R, Desai PD, Hawkins DT, Gleiser M, Kelley KK. Selected values of the thermodynamic properties of elements. Metals Park: American Society for Metals; 1973.Google Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2012

Authors and Affiliations

  • Rimpi Dawar
    • 1
  • R. Pankajavalli
    • 1
  • J. Joseph
    • 1
  • S. Anthonysamy
    • 1
  • V. Ganesan
    • 1
  1. 1.Chemistry Group, Indira Gandhi Centre for Atomic ResearchKalpakkamIndia

Personalised recommendations