X-Ray scattering study of ionic colloidal crystals

The scattering study of ionic colloidal crystals by using one- and two-dimensional ultra-small-angle scattering techniques is reviewed with a special reference to dilute dispersions. Because of large lattice constants of colloidal crystals, ultra-small angle regions need to be covered either by long distance optical systems combined with a synchrotron X-ray source or by adopting the Bonse–Hart optics. The crystal structure, lattice constant, and crystal orientation can be precisely determined.