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Mechanism and Cationic Rearrangements Involved in the Reduction of Co2+[Co2-x3+Crx3+]O42− Spinels

  • P. Bracconi
  • L. Berthod
  • L. C. Dufour

Abstract

This work deals with the Co(II, III)-Cr(III) oxide series (or Co3O4-CoCr2O4 solid solutions) with compositions ranging from Co3O4 to CoCr2O4. These oxides crystallize in the spinel structure and, according to Makkonen, their lattice parameter increases linearly with their Cr content from 8.08 Å for Co3O4 to 8.33 Å for CoCr2O4 (1). They are paramagnetic above Tc(CoCr2O4) = 100°K and TN (Co3O4) = 40°K. From their Curie constants we show that the Co3+ ions have a zero magnetic moment and, thus, are in a low spin state in octahedral sites (B), the moment of tetrahedral (A) Co2+ being 4.6 ~ 4.7 µ B. Whence the formula:

Keywords

Octahedral Site Spinel Structure Hydrogen Reduction Curie Constant Oxide Series 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    P. Porta, F.S. Stone and R.G. Turner, J.Solid State Chem., 11, 135 (1974).CrossRefGoogle Scholar
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    F. Pepe, P. Porta and M.Schiavello, this Symposium p.183)Google Scholar
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    E.J.W. Verwey and E.L. Heilmann, J.Chem.Phys., 15, 174 (1947)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1977

Authors and Affiliations

  • P. Bracconi
    • 1
  • L. Berthod
    • 1
  • L. C. Dufour
    • 1
  1. 1.Laboratoire de Recherches sur la Réactivité des Solides, Dept BFaculté des Sciences MirandeDijonFrance

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