  It has been experimentally established in numerous cases that precipitation
of monodispersed colloids from homogeneous solutions is a complex process.
Specifically, it was found that in many systems nuclei, produced rapidly in a
supersaturated solution, grow to nanosize primary particles (singlets), which
then coagulate to form much larger final colloids in a process dominated by
irreversible capture of these singlets. This paper describes a kinetic model
that explains the formation of dispersions of narrow size distribution in such
systems. Numerical simulations of the kinetic equations, with experimental
model parameter values, are reported. The model was tested for a system
involving formation of uniform spherical gold particles by reduction of auric
chloride in aqueous solutions. The calculated average size, the width of the
particle size distribution, and the time scale of the process, agreed
reasonably well with the experimental values.
