Oxygen-17 NMR Shifts in Aqueous Solutions of Rare-Earth Ions

Paramagnetic and diamagnetic shifts of the O17 NMR signal in aqueous solutions of the rare-earth ions at room temperature have been observed. The shift arises from the isotropic part of the hyperfine interaction between the O17 nucleus and the thermal average value of the spin of the rare-earth ion. The direction of the shift is in all cases opposed to the spin magnetization of the rare-earth ion. This result is explained through the formation of covalent bonds in the hydrated ion involving the rare-earth 6s orbital.