Magnetic Approach in Some Mixed Cobalt(Ii) Hydroxynitrates Compounds

Among layered compounds, the transition metal hydroxynitrates M(OH)(2-x)(NO3)(x).nH(2)O (with M= Co, Ni,Cu) are still currently investigated, since they are good precursors for the synthesis of simple or mixed metal oxides with interesting catalytic and electronic properties. From a structural point of view, the hydroxynitrates derive from the CdI2 type Stucture of M (OH)(2). They can be described as 2D triangular arrays of metal ions with large interplanar distances, and accordingly, they are good candidates for studying bidimensional magnetic systems. Knowing that from a magnetic point view, Co(OH)(2) and Co-2(OH)(3)(NO3) were shown to be a genuine examples of layered ferromagnetic systems, with the occurrence of 3d antiferromagnetic order at nearly the same temperature; we report in this paper the preparation and magnetic properties of layered cobat mixed metal(II) hydroxynitrates CoM(OH)(3)(NO3) (M= Cu, Ba) hydrated or no which display, according to the metal ion, either ferro or antiferromagnetic interlayer interactions. We discuss the interest in these compounds named hybrid organic-inorganic compounds for the stabilizing ferromagnetic interactions.