89Yttrium nuclear magnetic resonance studies
With a Fourier-transform spectrometer, especially developed for nuclei with weak NMR signals, the lines of89Y have been investigated in aqueous solutions of Y(NO3)3, YCl3, and Y(ClO4)3. The concentration dependence of the chemical shifts of the89Y resonance frequencies in these solutions were measured. Using this dependence, the Larmor frequency of the89Y3+ ion solely surrounded by water was determined by extrapolation. The Larmor frequency of89Y was referred to those of2H,39K, and73Ge with high accuracy. The magnetic moment of the89Y3+ ion purely surrounded by H2O molecules is μ(89Y3+) = −0.1368523(4) μN. The concentration dependence of Y(NO3)3 solutions in D2O yields the solvent isotope effect δ(89Y3+ in D2O)−δ(89Y3+ in H2O)= −(4.3±0.5)ppm. The89Y relaxation times T1 and T2 of a 3 molal aqueous Y(NO3)3 solution were determined in the pH range −0.5...+1.25. T1 190...90 s is nearly constant in this range, whereas the transverse relaxation rate T2−1 increases strongly with increasing pH; this effect seems to be due to the chemical exchange of the hydrated Y3+ ion between a monomer and a polymer site.