In this paper the characteristics of the concentration of donor atoms in ionic crystal with colloidal particles are discussed. It is shown that the concentration of donor atoms is independent of the concentration of impurity. At the late period of growth of colloidal particles, the concentration of donor atoms can be approximately represented by the critical concentration of impurity. At that period the "equilibrium" between donor atoms and colloidal particles does not imply that the free energy of the system is located at its minimum point, and it implies that the free energy of the system decreases slowly. From the point of view of diffusion of impurity atoms the physical picture of the growth of colloidal particles is described, and the growth speed of colloidal particle is discussed.The critical states and parameters Eβ, β for KC1, KBr, KI, and NaCl are discussed quantitatively, and the thermal coagulation and the optical coagulation are discussed qualitatively.It is pointed out that all discussions can be applied in the atomic crystals and alloys after some corrections.