Nuclear Magnetic Resonance and the Mobility of Water in CsMnCl3·2H2O

The ¹H, ²D, ³⁵Cl, and ¹³³Cs NMR of CsMnCl₂·2H₂O single crystals have been studied. The proton positions could be determined from the observed shift and dipolar splitting and the deuteron positions from the nuclear quadrupole interaction. Conclusions about the hydrogen bonding network were drawn. The rate of the H₂O and D₂O reorientation was examined by NMR linewidth measurements at different temperatures and an activation energy of 8.4 kcal/mole computed. Positions and reorientation rate showed no measurable isotope effects. The NMR of the two chlorine sites at room temperature gave ${\nu }_q\text{\hspace{0.17em}=\hspace{0.17em}6.106}\mathrm{Mc}/\sec$ , $\text{η\hspace{0.17em}=\hspace{0.17em}0.285}$ for the bridged chlorine (Mn–Cl–Mn) and ${\nu }_q\text{\hspace{0.17em}=\hspace{0.17em}4.192}\mathrm{Mc}/\sec$ , $\text{η\hspace{0.17em}=\hspace{0.17em}0.727}$ for the single bonded (Mn–Cl). In both cases a hyperfine interaction of $A_s{\text{\hspace{0.17em}=\hspace{0.17em}1.30\hspace{0.17em}×\hspace{0.17em}10}}^{\text{−4}}{\mathrm{cm}}^{\text{−1}}$ and $A_p{\text{\hspace{0.17em}=\hspace{0.17em}0.14\hspace{0.17em}×\hspace{0.17em}10}}^{\text{−4}}{\mathrm{cm}}^{\text{−1}}$ was calculated from the observed paramagnetic shifts. The quadrupole coupling and magnetic shift tensors of ¹³³Cs were measured and from the linewidth and saturation the relaxation times estimated.