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Journal of Thermal Analysis and Calorimetry

, Volume 122, Issue 2, pp 571–578 | Cite as

Thermolysis mechanism of dysprosium hexahydrate nitrate Dy(NO3)3·6H2O and modeling of intermediate decomposition products

  • P. Melnikov
  • I. V. Arkhangelsky
  • V. A. Nascimento
  • A. F. Silva
  • L. C. S. de Oliveira
  • L. Z. Zanoni Consolo
  • A. S. Herrero
Article

Abstract

The thermal decomposition of dysprosium nitrate is a complex process which begins with the simultaneous condensation of the initial monomer Dy(NO3)3·6H2O into a cyclic hexamer 6[Dy(NO3)3·6H2O]. This cluster gradually loses water and nitric acid, and intermediate oxynitrates Dy6O7(NO3)4·6H2O and Dy6O8(NO3)2·5H2O are formed. At higher temperatures, these products undergo further degradation, lose nitrogen dioxide, water, and oxygen, and finally, after having lost lattice water, are transformed into the cubic form of dysprosium oxide. The models of intermediate oxynitrates represent a reasonably good approximation to the real structures and a proper interpretation of experimental data. The comparison of the potential energies of consecutive oxynitrates permitted an evaluation of their stability. The mechanism was studied by thermal analysis, differential scanning calorimetry, infrared spectroscopy, and X-ray diffraction. The mass losses were related to the vibrational energy levels of the evolved gases.

Keywords

Rare earth Dysprosium nitrate hexahydrate Thermal decomposition Oxynitrates Computer modeling 

Notes

Acknowledgements

The authors are indebted to CNPq and FUNDECT (Brazilian agencies) for financial support.

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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2015

Authors and Affiliations

  • P. Melnikov
    • 1
  • I. V. Arkhangelsky
    • 2
  • V. A. Nascimento
    • 1
  • A. F. Silva
    • 1
  • L. C. S. de Oliveira
    • 3
  • L. Z. Zanoni Consolo
    • 1
  • A. S. Herrero
    • 3
  1. 1.School of MedicineUFMSCampo GrandeBrazil
  2. 2.School of ChemistryMoscow State UniversityMoscowRussia
  3. 3.School of ChemistryFederal University of Mato Grosso do SulCampo GrandeBrazil

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