Magnetic and Mössbauer study of some transition metal based nitroprussides

Abstract Susceptibility data of freshly precipitated nitroprussides TM[Fe(CN) 5 NO] n H 2 O (TM=Mn, Fe, Co, Ni, Cu) follow very well modified Curie–Weiss law down to T =5 K indicating paramagnetic state; nitroprusside (NP) containing Zn is diamagnetic with a sign of paramagnetic contribution. Deviation from Curie–Weiss law and magnetization measurements on MnNP, FeNP and CoNP below T =5 K can indicate ferrimagnetic ordering at low temperatures. A hysteresis behaviour in ZFC and FC magnetisation with the temperature of bifurcation T b =6 K was found for CoNP and FeNP. Mossbauer spectra taken at room temperature (besides FeNP) consist of a single symmetric quadrupole-split doublet with parameters δ and Δ typical for Fe II ions in octahedral sites. A more complicated spectrum of FeNP is a consequence of different Fe environments.