Effect of Paramagnetic Ions on the Nuclear Magnetic Resonance of O17 in Water and the Rate of Elimination of Water Molecules from the First Coordination Sphere of Cations

Abstract

Observations have been made on the relative effectiveness of various paramagnetic ions in broadening the nuclear magnetic resonance of O17 in water and it is inferred that the relaxation occurs almost entirely in the first coordination sphere of all of the cations studied except chromic ion. Accepting this hypothesis, it is possible to calculate lower limits for the rates of exchange of bulk water molecules with those in the first coordination sphere of the cations. For ferric ion the lifetime of a coordinated water molecule is equal to or less than 10—6 second at room temperature.