Abstract
Various types of ion-pairs of different systems involving tetra-
n-butylammonium iodide (D) with antimony trichloride (A) in dilute solutions in acetonitrile, methylene chloride and chloroform have been investigated spectrophotometrically in the region 550—25O mn. Their composition, stability constant, and free energy of formation have been calculated. The stability constant of the complex is related very much to its stoichiometry. The complex of acetonitrile system has the form D.A
2 whereas D.A is the form of methylene chloride and chloroform systems. The energy difference of the two peaks of the spectrum was compared with the
2
P
3
2
—
2
P
1
2
energy interval of the iodine atom. A comparison of the stability values has been discussed in relation to the polarizability and the dielectric constant of the environment used. A model attained by the ion in the solution may play a considerable role in the mechanism of ion-pairs interaction.