Catena-poly[[bis[pentaaquaerbium(III)]-mu-benzenehexacarboxylato] tetrahydrate]

The title compound is composed of one-dimensional polymeric [[Er(2)(C(12)O(12))(H(2)O)(10)].4H(2)O](n) chains containing Er in a slightly distorted antiprismatic eightfold coordination. The benzenehexacarboxylate ion is located about an inversion centre. Water molecules of crystallization, linked by hydrogen bonding to water molecules of the rare earth coordination spheres or the carboxylate groups of the organic ligands, fill the space generated by the packing of the separated chains.