Based on the results of studying the coagulation kinetics of monodisperse sol of SiO₂ in NaCl solutions at various pH values, it is shown that the coagulation rate, flowing in the far potential minimum while maintaining a high repulsion barrier between the particles, depends on the formation and decomposition times of the aggregates. The boundary values of the depth and power of the far potential minimum—at the excess of which sol coagulates—are determined.