Layered [BaM(C 3 H 2 O 4 ) 2 (H 2 O) 4 ] (M = Fe or Co) Complexes − Spectroscopic, Magnetic and Thermal Study

Complexes with formula [BaM(C 3 H 2 O 4 ) 2 (H 2 O) 4 ], where M = Fe or Co, were synthesised and characterised. These two types of complexes are isostructural and crystallise in the Pccn space group. Their structure consists of two‐dimensional networks of octahedral MO 6 polyhedra in which the transition metal ions are coordinated by bridging malonate ligands, through the O‐C‐O atoms. These M‐malonate units are extended along the crystallographic [101] plane. Spectroscopic data are consistent with the cations being in a high‐spin octahedral symmetry. The two types of compounds exhibit 2D antiferromagnetic interactions as well as weak ferromagnetism below the Néel temperature, as a result of an intralayer misalignment of the spins. Thermal treatment of the metallo‐organic precursors gave rise to BaMO 3−y oxides at lower temperatures and reaction times than those found in the literature using the ceramic method. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).