Synthesis, structure and magnetic properties of Na9Co2O7, a new mixed-valent 
sodium cobaltate(II,III)

Sofin, M.; Peters, E.-M.; Jansen, M.

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Synthesis, structure and magnetic properties of Na₉Co₂O₇, a new mixed-valent sodium cobaltate(II,III)

MPS-Authors

/persons/resource/persons280534

Sofin, M.
Abteilung Jansen, Former Departments, Max Planck Institute for Solid State Research, Max Planck Society;

/persons/resource/persons280381

Peters, E.-M.
Former Scientific Facilities, Max Planck Institute for Solid State Research, Max Planck Society;

/persons/resource/persons280091

Jansen, M.
Abteilung Jansen, Former Departments, Max Planck Institute for Solid State Research, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Sofin, M., Peters, E.-M., & Jansen, M. (2004). Synthesis, structure and magnetic properties of Na₉Co₂O₇, a new mixed-valent sodium cobaltate(II,III). Solid State Sciences, 6(4), 339-344.

Cite as: https://hdl.handle.net/21.11116/0000-000E-F6ED-2

Abstract

Na9CO2O7 was prepared via the azide/nitrate route. Stoichiometric
mixtures of the precursors (Co3O4, NaN3 and NaNO3) were heated in a
special regime up to 450 degreesC and annealed at this temperature for
100 h in specially designed silver containers. Single crystals have
been grown by annealing a Na2O/Na9CO2O7 mixture (molar ratio 1:2) at
500 degreesC for 2000 h in silver crucibles, which were sealed in glass
ampoules under dried Ar. According to the X-ray analysis of the crystal
structure (Pca2(1), Z = 4, a = 9.5477(6) Angstrom, b = 9.9040(6)
Angstrom, c = 10.1919(7) Angstrom, 4103 independent reflections, R-1 =
5.23% (all data)) there are isolated (CoO4)-O-III tetrahedra and
(CoO3)-O-II triangles. Na9Co2O7 is isostructural to Na9Fe2O7, and shows
Curie-Weiss behaviour down to similar to 25 K. The best fit (for Co-II
(S = 3/2) and Co-III (S = 2)) yields an average value of the magnetic
moment (per cobalt) mu = 3.23mu(B) (g = 2.07) and Theta = -6 K. At 20 K
one observes an onset of ferromagnetic order. (C) 2004 Elsevier SAS.
All rights reserved.