Poly[[aqua­tris­(μ(4)-benzene-1,2-dicarboxyl­ato)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 carboxyl­ate-O atoms from six benzene-1,2-dicarboxyl­ate (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 carboxyl­ate-O atoms from six BDC anions and a coordinated water mol­ecule. 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 inter­action is also present in the crystal structure. The uncoordinated water molecule shows half-occupation.