Calculation of single-ion partition coefficients

Single-ion partition coefficients have been calculated for NBu ₄ ⁺ and I⁻ in the system water—chloroform. The standard free energy of transfer of each ion was separated into an electrostatic and a neutral term. The electrostatic term was calculated with the aid of the Born equation. In the case of I⁻ the neutral term was calculated with the aid of the xenongas assumption, whereas in the case of NBu ₄ ⁺ the tetrabutylmethane assumption was used. The results of the calculation were compared with the experimentally found partition coefficient of the completely dissociated ion-pair NBu₄I.