107Ag and 109Ag Nuclear Magnetic Resonance Studies of Ag+ Ions in Aqueous Solutions

Abstract

The NMR lines of 107Ag and 109Ag have been investigated in aqueous solutions of AgF, AgNO3, and AgClO4. The ratio of the Larmor frequencies of 109Ag and 107Ag has been measured in various samples: ν(109Ag)/ν(107Ag) = 1.149 639 7 (8). No primary isotopic effect was to be detected within these limits of error (0.7 ppm). This ratio yields the hyperfine structure anomaly 107⊿109 = − 0.004127 7(7). The concentration dependence of the chemical shift of the 107Ag and 109Ag resonance frequencies was determined. Using this dependence, the ratios of the Larmor frequencies of the 107Ag and 109Ag nuclei for infinite dilution relative to the resonance frequency of 73Ge in GeCl4 are given. The magnetic moments of the 107Ag+ and 109Ag+ ions merely surrounded by water molecules are μ(107Ag+) = − 0.113 045 3(9) μN and μ(109Ag+) = − 0.129 961 5(10) μN without diamagnetic corrections. These values are compared with the result of an atomic beam experiment, the difference of the moments is due to the shielding of the silver nuclei by water molecules around the ions. The shielding constant is σ* (Ag+ in H2O vs. Ag atom) = − 0.000 94(17). Preliminary values of the relaxation times are given.