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Study of the nature of the crystallization water in some magnesium hydrates by thermal methods

Abstract

The nature of the crystallization water in MgSO4·7H2O, Mg(NO3)2·6H2O and MgCl2·6H2O has been studied with the nonisothermal methods of thermogravimetry (TG), derived thermogravimetry (DTG) and differential thermal analysis (DTA).

Analysis of the characteristic thermogravimetric data (T M,W ) and the kinetic parameters (n, E a), together with the DTA results, with CuSO4·5H2O as control sample, provided evidence of the existence of coordinated water and of the nature of the anions in these hydrates.

The results are confirmed by the observation of a real compensation effect. For the compensation effect, the following equation is proposed: InA=0.220E-0.8

Structures explaining the presence of the coordinated water and the nature of the anions in these hydrates are also proposed.

Zusammenfassung

Mittels nichtisothermer Methoden der Thermogravimetrie (TG), Derivationsthermogravimetrie (DTG) und Differentialthermoanalyse (DTA) wurde die Art des Kristallwassers in den Verbindungen MgSO4·7H2O, Mg(NO3)2·6H2O und MgCl2·6H2O untersucht. Eine Analyse der charakteristischen thermogravimetrischen Angaben (T M,W ) und der kinetischen Parameter (n, E a) zusammen mit den DTA-Ergebnissen (mit CuSO4·5H2O) als Referenzprobe) lieferten den Beweis für die Existenz koordinierten Wassers und für die Art der Anionen in diesen Hydraten.

Die Ergebnisse wurden durch die Beobachtung eines tatsächlichen Kompensationseffektes bestätigt. Für den Kompensationseffekt wird nachstehende Gleichung empfohlen: lnA=0.220E-0.8. Weiterhin wurden Strukturen vorgeschlagen, welche die Gegenwart von koordiniertem Wasser und die Natur der Anionen in diesen Hydraten erklären.

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References

  1. 1

    D. Negoiu, Tratat de Chimie anorganica II, Editura tehnicâ, Bucure§ti 1972, a) p. 248; b) p. 350; c) p. 358; d) p. 356.

    Google Scholar 

  2. 2

    J. Paulik, F. Paulik and L. Erdey, Microchim. Acta, (1966) 886.

  3. 3

    J. Paulik, F. Paulik and L. Erdey, Anal. Chim. Acta, (1966) 419.

  4. 4

    E. L. Simmons and W. W. Wendlandt, Thermochim. Acta, 2 (1971) 465.

    CAS  Article  Google Scholar 

  5. 5

    T. P. Herbells, Thermochim. Acta, 4 (1972) 295.

    Article  Google Scholar 

  6. 6

    C. Duval, Inorganic Thermogravimetric Analysis, Elsevier Publishing Company, Amsterdam 1963 a) p. 217; b) p. 218.

    Google Scholar 

  7. 7

    A. B. Phadmis and V. V. Desparide, Thermochim. Acta, 43 (1981) 249.

    Article  Google Scholar 

  8. 8

    H. Tanaka and N. Koga, Thermochim. Acta, 133 (1988) 221.

    CAS  Article  Google Scholar 

  9. 9

    S. Shaval, S. Variv, V. Kirsh, Thermochim. Acta, 133 (1988) 263.

    Article  Google Scholar 

  10. 10

    E. Urbanovici and E. Segal, Proc. Natl. Symp. Thermal. Anal. 8th, 1991, p. 55.

  11. 11

    N. Koga and H. Tanaka, Thermochim. Acta, 183 (1991) 125.

    CAS  Article  Google Scholar 

  12. 12

    C. Popescu and E. Segal, Rev. Roum. Chim., 37 (1992) 113.

    CAS  Google Scholar 

  13. 13

    E. H. Kim, J. J. Park, J. H. Park, J. S. Chang, C. S. Choi, Thermochim. Acta, 196 (1992) 495.

    CAS  Article  Google Scholar 

  14. 14

    N. Koga and H. Tanaka, Thermochim. Acta, 209 (1992) 127.

    CAS  Article  Google Scholar 

  15. 15

    P. M. Modhusudanan, K. Krishnan and K. N. Ninon, Thermochim. Acta, 221 (1993) 13.

    Article  Google Scholar 

  16. 16

    E. S. Freeman and B. Carroll, J. Phys. Chem., 62 (1958) 394.

    CAS  Article  Google Scholar 

  17. 17

    A. W. Coats and J. T. Redfern, Nature (London), 201 (1964) 68.

    CAS  Article  Google Scholar 

  18. 18

    N. Hurduc, L. Odochian, C. Vasile, St. Ungureanu and D. Gilea, Metode experimentale in cinetica chimicâ cu prelucrarea datelor pe calculator, Institutul Politehnic la§i, 1979, a) p. 138; b) p. 189.

  19. 19

    N. Hurduc, C. Vasile and L. Odochian, Bull. Inst. Politehnic Ia§i, 1–4, (1982) 47.

    Google Scholar 

  20. 20

    A. V. Nikolaev, V. Logvinenko and V. M. Gorbachev, J. Thermal Anal., 6 (1979) 473.

    Article  Google Scholar 

  21. 21

    A. V. Nikolaev and V. A. Logvinenko, J. Thermal Anal., 10 (1976) 363.

    CAS  Article  Google Scholar 

  22. 22

    V. M. Gorbachev, J. Thermal Anal., 8 (1975) 585.

    CAS  Article  Google Scholar 

  23. 23

    V. M. Gorbachev, J. Thermal Anal., 9 (1976) 121.

    CAS  Article  Google Scholar 

  24. 24

    E. Segal and D. Fâtu, Introducere in cinetica neizotermâ, Editura Academiei, Bucure§ti 1983, p. 189.

    Google Scholar 

  25. 25

    C. Vasile, E. Costea and L. Odochian, Thermochim. Acta, 184 (1991) 305.

    CAS  Article  Google Scholar 

  26. 26

    N. Hurduc and D. Ionescu, Cellulose Chem. and Technol., 26 (1992) 41.

    Google Scholar 

  27. 27

    J. Zsakó, Cs. Várhelyi, G. Liptay and K. Szilágyi, J. Thermal Anal., 7 (1975) 41.

    Article  Google Scholar 

  28. 28

    P. Pascal, Nouveau traité de Chimie Minérale, Masson et Cie éditures, Paris, 1956, p. 427.

    Google Scholar 

  29. 29

    C. Drâgulescu and E. Petrovici, Introducere in Chimia anorganicâ modernâ, Editura Facla, Timi§oara, 1973, p. 296.

    Google Scholar 

  30. 30

    G. J. Janz, Estimation of Thermodynamic Properties of Organic Compounds, Pergamon, New York 1967, p. 132.

    Google Scholar 

  31. 31

    H. Tanaka and N. Koga, Thermochim. Acta, 133 (1988) 227.

    CAS  Article  Google Scholar 

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Odochian, L. Study of the nature of the crystallization water in some magnesium hydrates by thermal methods. Journal of Thermal Analysis 45, 1437–1448 (1995). https://doi.org/10.1007/BF02547437

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Keywords

  • crystallization water
  • DSC
  • kinetics
  • magnesium hydrates
  • TG-DTG-DTA