Structural, Magnetic And Mossbauer Studies Of The Molecular Ferromagnet Compounds Nbu(4)[Mcr(C2o4)(3)](Bu=(Ch2)(3)Ch3, M=Mn, Fe)

An X-ray study of a single crystal of the NBu(4)[MnCr(C2O4)(3) composition reveals a layered structure with an ordered arrangement of Mn2+ and Cr3+ ions. According to the data of the orientation dependence of magnetization at 4.5K, the magnentic easy axis is aligned along the crystal c-axis. Mossbauer data analysis of isostructural NBu(4)[FeCr(C2O4)(3)] powder material gives, on the contrary, the evidence of strong confinement of Fe2+ spins to the crystal basal plane. The ferromagnetic system which arises here is a quasi-2D system in terms of the nature of its exchange interactions.