Production of Sb(IV) Chloro Complex by Flash Photolysis of the Corresponding Sb(III) and Sb(V) Complexes in CH3CN and CHCl3

[SbCl6]2- was formed in the flash photolysis of [SbCl6]3- or [SbCl6]- in both solutions of CH3CN and CHCl3 in the presence of an excess of chloride. [SbCl6]2- had absorption maxima at 293, 328, and 390 nm in CH3CN. A similar absorption spectrum of [SbCl6]2- was also obtained in CHCl3. The lifetime of [SbCl6]2- was much shorter in CHCl3 than in CH3CN. [SbCl6]- was easily reduced to [SbCl6]3- upon continuous UV-irradiation in CH3CN as well as in CHCl3. On the other hand, [SbCl6]3- was oxidized to [SbCl6]- in CHCl3 in the presence of oxygen, but was not in CH3CN. The spectrum and the decay rate of [SbCl6]2- were not essentially affected by oxygen in both solutions of CH3CN and CHCl3.