  Monte Carlo simulations have been performed for aqueous charged colloidal
suspensions as a function of charge density on the particles and salt
concentration. We vary the charge density in our simulations over a range where
a reentrant solid-liquid transition in suspensions of silica and polymer latex
particles has been reported by Yamanaka et al. [Phys. Rev. Lett. 80 5806
(1998)]. We show that at low ionic strengths a homogeneous liquid-like ordered
suspension undergoes crystallization upon increasing charge density . Further
increase in charge density resulted once again a disordered state which is in
agreement with experimental observations. In addition to this reentrant
order-disorder transition, we observe an inhomogeneous to homogeneous
transition in our simulations when salt is added to the disordered
inhomogeneous state. This inhomogeneous to homogeneous disordered transition is
analogous to the solid-gas transition of atomic systems and has not yet been
observed in charged colloids. The reported experimental observations on charged
colloidal suspensions are discussed in the light of present simulation results.
