Single-ion partition coefficients have been calculated for NBu
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
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.