Journal of Materials Science

, Volume 42, Issue 13, pp 4778–4784 | Cite as

Synthesis and physical properties of new oxide AgMnO2

  • Nesrine Koriche
  • Aissa Bouguelia
  • Mohamed Mohammedi
  • Mohamed TrariEmail author


A novel oxide AgMnO2 was prepared from LiMnO2 via Ag→ Li+ exchange in the eutectic melt AgNO3-KNO3. It crystallizes in a monoclinically distorted unit cell (SG C2/m) caused by the Jahn-Teller (J-T) ion Mn3+ (3d 4). The structure was refined by isotypy with the crednerite CuMnO2. There are two long axial Mn–O of 264.2(0) pm and four equatorial bonds of 192.7(3) pm and Mn–O–Mn adjoining (83.07°) are bent below the ideal angle. The thermal variation of the magnetic susceptibility (χ/T 1) obeys a Curie-Weiss law with manganese in a trivalent, high spin (HS) state accommodated in elongated MnO6 octahedra (14.8%). Direct coupling between Mn3+ involves negative exchange interactions through long-range antiparallel moments with a temperature θ p  = −436 K and a magnetic moment of 5.26 μB/Mn3+ slightly larger than the spin only moment. The title oxide is stable in air up to ∼680 °C before it decomposes into metal silver. It displays a semi-conducting behavior with an activation energy of ∼0.45 eV, characteristic of a conduction by low mobility polarons between Ag+/2+ where nearly all polarons are bonded. The photoelectrochemical properties of AgMnO2 have been investigated by photocurrent technique in 1 M KOH. The cathodic photocurrent J ph provides unambiguous evidence of p-type character attributed to oxygen insertion (0.025 oxygen by formula unit) as required by the charge compensating mechanism. The valence band is made up of Ag−4d wave functions positioned at ∼5.14 eV below vacuum. A comparison with CuMnO2 was also reported.


MnO2 High Spin Small Polaron Photoelectrochemical Property Edge Shared Octahedra 
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.



This work was supported financially be the Faculty of Chemistry (Algiers) under the contract N° E1602/04/2000. The authors are grateful to Mr A. Mokhtari for his general assistance.


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Nesrine Koriche
    • 1
  • Aissa Bouguelia
    • 1
  • Mohamed Mohammedi
    • 2
  • Mohamed Trari
    • 1
    Email author
  1. 1.Faculté de Chimie, Laboratoire de Stockage et de Valorisation des Energies RenouvelablesUSTHBAlgiersAlgeria
  2. 2.Ecole Polytechnique EMPAlgiersAlgeria

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