Here again [2(1A)6] or [2(1B)6] are similar, with two angles around 64° and four angles between 70 and 80°; in [2(1C)6] and [2(1D)6] one angle is around 32° and four between 80 and 90°. These are subtle changes which are presumably due to crystal packing as there seems no obvious steric explanation. To determine whether the structures are maintained in solution, and to examine the conformational flexibility in the [2(1X)6] family, we measured SAXS data on all four [7]rotaxanes (Figure ). Each of the experimental SAXS data show three main peaks which vary in intensity depending on the structure.