When dispersed particles or solute ions have high charge densities, macroscopically homogeneous systems become microscopically inhomogeneous. Examples are the two-state structure of ordered structures in disordered region without boundary and the void structures. When the charge density is increased, the reentrant phase (liquid-solid-liquid) transition is found, which is not explainable in terms of the repulsion-only assumption. Furthermore, for relatively small charge particles and at an early stage of crystallization, space-filling ordered states are first formed, disordered regions are then created inside the ordered domains, and crystal contraction thereafter takes place, causing the two-state structure. These may be explained by invoking a counterion-mediated attractive interaction between like-charged entities in addition to the widely accepted repulsion-only assumption. ©2000 American Institute of Physics.