Poly[[aqua-tris-(μ(4)-benzene-1,2-dicarboxyl-ato)dilanthanum(III)] hemihydrate]

The asymmetric unit of the title coordination polymer, {[La(2)(C(8)H(4)O(4))(3)(H(2)O)]·0.5H(2)O}(n), contains two independent La(III) atoms, one of which is surrounded by eight carboxyl-ate-O atoms from six benzene-1,2-dicarboxyl-ate (BDC) anions in a bicapped trigonal-prismatic geometry. The other La(III) atom is nine-coordinated in a tricapped trigonal-prismatic geometry, formed by eight carboxyl-ate-O atoms from six BDC anions and a coordinated water mol-ecule. The BDC anions bridge the La(III) atoms, forming a two-dimensional polymeric complex parallel to (001). The crystal structure contains weak O-H⋯O and non-classical C-H⋯O hydrogen bonds. A C-H⋯π inter-action is also present in the crystal structure. The uncoordinated water molecule shows half-occupation.