Journal of Thermal Analysis and Calorimetry

, Volume 102, Issue 1, pp 91–97 | Cite as

Determination of the structural formula of sodium tris-carbonatocobaltate(III), Na3[Co(CO3)3]·3H2O by thermogravimetry

  • Fikru Tafesse
  • Elias Aphane
  • Elizabeth Mongadi


The existence of an inner sphere water in sodium tris-carbonatocobaltate(III) prepared by the Bauer and Drinkard method was confirmed by thermogravimetry, which led to its formulation as sodium aquo-tris-carbonatocobaltate(III) dihydrate, Na3[Co(H2O)(CO3)3]·2H2O. Hydrolytic study on 4-nitrophenylphosphate promoted by [Co(tn)3]3+ afforded corborating evidence for the existence of inner sphere water in the complex leading to its formulation as [Co(tn)3(H2O)]3+. Another variety of the tris-carbonato anion, [Co(NH3)6][Co(CO3)3], was prepared and subjected to thermogravimetric analysis, and the absence of inner sphere water in the compound was confirmed. The plausible existence of inner sphere water for the compounds that emanate from the synthetic routes utilizing the Bauer and Drinkard method in the crystalline phase is proposed.


Structural formula Sodium tris-carbonatocobaltate(III) Elemental analysis Thermogravimetric analysis Hydrolysis of 4-nitrophenylphosphate Microemulsions 



The financial support rendered to us by the NRF and the Ecotoxicology niche area of the Department of Chemistry, UNISA, is gratefully acknowledged. We would also like to thank Dr. E.M. Van der Merwe (University of Pretoria), Prof. S.O. Paul (UNISA) and Prof. R.B. Jordan (University of Alberta) for their advice.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2009

Authors and Affiliations

  • Fikru Tafesse
    • 1
  • Elias Aphane
    • 1
  • Elizabeth Mongadi
    • 1
  1. 1.Department of ChemistryUniversity of South AfricaPretoriaSouth Africa

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