Proton-Magnetic-Resonance Study of Barium Bromide Monohydrate

The proton-magnetic-resonance doublets were obtained for rotation of the crystal around its c axis. From these data, the proton-proton separation was computed to be 1.56±0.02 A. The hydrated water molecule was found to lie in one orientation whose proton-proton axis makes direction angles of α0=89±1°, β0=1±1°, and γ0=90±6°, measured from the positive a, b, and c crystallographic axes, respectively. This orientation fits well into the crystal structure and indicates that the complex, BrI— —H–O–H— —BrII, exists. Line widths range from 6.5 to 4.2 gauss and show a correlation with T1 as a function of orientation. Observation was necessarily made with some saturation. A new effect, an asymmetry of line areas in the doublets, was observed for narrow ranges near two crystal orientations. The two orientations were symmetrically close to that for which the proton-proton line was parallel to the external magnetic field. It may be due to crossing of the barium quadrupole resonance frequencies over the magnetic-resonance frequencies of the protons.