Thermal behavior of the coordination compound [Co(urea)6](NO3)2
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The coordination compound [Co(urea)6](NO3)2 was synthesized and physico-chemically characterized. The thermal decomposition carried out in dynamic air and inert atmosphere under non-isothermal conditions has been investigated by means of combined thermogravimetry/mass spectrometry, X-ray diffraction, IR and UV-VIS spectroscopy as well as magnetic measurements. The course of the thermal decomposition starts with two-phase transitions (melting and a Oh→Tdconfiguration change of the Co2+ ion) and continues with seven mass loss steps. According to the thermogravimetric and magnetic investigations a dimeric compound, [Co(biuret)(NCO)]2(NO3)2, is assumed to arise. Up ~250°C, an oxohydroxide nitrate intermediate is formed and a gradual oxidation of the Co2+ ions is observed. At 550°C, Co3O4 with mean crystallite sizes of ~150 Ĺ is identified.
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- 1.B. F. Hoskins, C. J. Mckenzie, I. A. S. Macdonald and R. Robson, J. Chem. Soc.-Dalton Transitions, 11 (1996) 227.Google Scholar
- 7.M. D. Hollingsworth and K. D. M. Harris, in J. L. Arwood, D. D. MacNicol, J. E. D. Davies, F. Vogtle, J. M. Lehn (Eds), Comprehenaive Supramolecular Chemistry, Vol. 4, Pergamon, Oxford 1966, Chap. 7, p. 177.Google Scholar
- 9.A. Yogodin, J. Therm. Anal. Cal., 38 (1998) 537.Google Scholar
- 10.A. Kozak, K. Wieczorek-Ciurowa and A. Pielichowski, J. Thermal Anal., 45 (1995) 1245.Google Scholar
- 12.G. Gyoryova and V. Balek, J. Thermal Anal., 40 (1993) 519.Google Scholar
- 15.L. Patron, O. Carp, I. Mindru, L. Petre and M. Brezeanu, Rev. Roum. Chim., 43 (1998) 173.Google Scholar
- 18.K. Nakamoto, Infrared Spectra of Inorganic and Coordination Compounds, Ed. 4, Wiley, London 1978.Google Scholar
- 20.A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier, Amsterdam 1968, Chap.9.Google Scholar
- 21.B. N. Figgis and J. Lewis, Prog. Inorg. Chem., 6 (1964) 37.Google Scholar
- 22.F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, Wiley 1966, p. 866.Google Scholar
- 25.O. Carp, Rev. Roum.Chim., 46 (2001) 735.Google Scholar