Abstract
Measurements of the nuclear relaxation times of the protons in dimethyl sulphoxide in solutions of low concentration of Ni(II) ions have been carried out between 12°c and 112°c. The results are interpreted in terms of chemical exchange between the coordination sphere of the paramagnetic ion and the bulk-solvent. The effect of the outer sphere contribution to the observed relaxation rates is considered and limiting parameters for the exchange process are obtained.