Dimerization of the reagent and the complex in the organic phase:

In the organic phase, the reagent and the ion pair can undergo dimerization and the relevant equilibria are

2 (R₄As⁺.Cl^-)_o ↔ (R₄As⁺. Cl ^- )_2o

KP = [(R₄As ⁺ .Cl ^-) ₂ ]_o/[(R₄As ⁺ .Cl ^-) ]²_o                                                                

And,

2[(R₄As⁺.MnO^-₄ ) ↔ (R ₄ As⁺.MnO ₄^- ) _2o

K'p = [(R₄As ⁺ . MnO^-₄) ₂ ]_o/[(R₄As ⁺ . MnO^-₄) ]²_o                                 

From the different equilibria, the distribution ratio of permanganate in the two phases can be described as under given below:

 D ≅ - [MnO^-₄]/[MnO^-₄]a = [(R₄As⁺.MnO₄)]_o +[(R₄As⁺.MnO₄^-)₂]_o/[MnO^-₄]_a+[(R₄As⁺.MnO₄^-)]

If the MnO^-₄   concentration is low, the dimer formation may be neglected.