Structure and thermal decomposition of poly[[triaqua(mu(4)-oxydiacetato)lanthanum(III)] nitrate]

Abstract

In the title lanthanum complex, {[La(C4H4O5)(H2O)(3)] NO3}(n), the lanthanum cation is immersed in a nine-coordinate environment provided by a tridentate oxydiacetate (oda) ligand ( through two carboxylate and one ether O atoms), three carboxylate O atoms from neighbouring oda ligands and three aqua ligands. The LaO9 polyhedra are interlinked into a tight three-dimensional framework, which leaves holes where the nitrate anions lodge. The links to the polymeric framework are by an extensive hydrogen-bonding scheme utilizing all the water H atoms. Thermogravimetric analysis shows that the three coordinated water molecules leave the structure in two well differentiated steps.