The first ferric carboxylate with a three-dimensional hydrid open-framework (MIL-82):: its synthesis, structure, magnetic behavior and study of its dehydration by Mossbauer spectroscopy

The new compound Fe-III(OH)[C6H2(CO2)(2)(CO2H)(2)].xH(2)O (with x = 0.88) is the first ferric carboxylate with a 3D open structure that has been synthesized up to now. Its structure is built up from chains of octahedra connected by carboxylate ligands; it displays small channels filled by water molecules. The removal of water molecules was studied by Mossbauer spectroscopy which set up defaults of water molecules in the crystal. Magnetic measurements indicate an antiferromagnetic behavior at low temperature, but also a metamagnetic transition for an applied magnetic field larger than 0.5 T. (C) 2004 Elsevier SAS. All rights reserved.