Chemistry Department, Tehran University, Tehran, I.R. IRAN
The nitrite ® nitro isomerization in nitritopentaamine cobalt (III) halides has been known. In this paper, the effect of the size of the counter ions (noncoordinated groups) on the rate of isomerization in nitritopentaamine cobalt (III) halides, is reported. The rate of isomerization is decreased by increasing the size of the counter ions. This decrease is explained on the basis of steric interaction between the nitro groups in the inner sphere and the counter ions in the outer sphere of these complexes.