Structure and thermal decomposition of poly[[triaqua(μ₄-oxydiacetato)lanthanum(III)] nitrate]

Abstract

In the title lanthanum complex, {[La(C(4)H(4)O(5))(H(2)O)(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.