Lanthanide contraction effect on crystal structures of lanthanide coordination polymers with cyclohexanocucurbit[6]uril ligand

The reaction of cyclohexanocucurbit[6]uril with lanthanide ions (La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, Dy3+, Ho3+, Tm3+ and Yb3+) under hydrochloric acid in the presence of CdCl2 resulted in eleven compounds, which demonstrate interesting lanthanide contraction effect and provide a means of separating lanthanide ions.194