ENTHALPIES OF TRANSFER OF CO(II), NI(II) AND CU(II) IONS IN ACETONITRILE-WATER MIXTURES

The enthalpies of solution have been measured for Ni(CLO(4))(2) . 6H(2)O, Cu(ClO4)(2) . 6H(2)O and water in acetonitrile-water mixtures over the whole range of solvent composition. These data have been used for calculation of the enthalpies of transfer of Ni(ClO4)(2) and Cu(ClO4)(2) from water to the mixtures. In the acetonitrile-rich mixtures an alternative method of determining the enthalpies of transfer has also been applied. The results, as well as our previous data for Co(ClO4)(2) [1], coupled with the enthalpies of transfer of perchlorate ion reported earlier [2], have allowed the determination of the enthalpies of transfer for Co(II), Ni(II) and Cu(II) ions in acetonitrile-water mixtures. The variation of the ionic enthalpies of transfer with solvent composition is discussed in terms of the properties of the ions and the solvents.