Deuteron magnetic resonance studies. Part 6.—Lithium deuteroxide deuterate

Abstract

A deuteron magnetic resonance study of single crystals of LiOD · D₂O at 82 K has shown that the crystal is ordered and that the deuteron quadrupole coupling constants and asymmetry parameters for the OD^– ion and D₂O molecule are OD^–(e²qQ/h)= 271.7 kHz, η= 0.04₃, D₂O (e²qQ/h)= 173.0 ± 0.9 kHz, η= 0.16₉± 0.005. The OD^– ion points along the c-axis of the crystal and the plane of the water molecule is perpendicular to the same direction, giving rise to strong but markedly non-linear O_h… O_w… O_h hydrogen bonds between the two species. The angle between the two maximum principal components of the quadrupole coupling tensor in one D₂O molecule is 107°15′, larger than that observed in D₂O vapour (101°59′), the difference being attributed largely to an expansion of the D[graphic omitted]D angle by 5 ± 2° when the water molecule enters the lattice of LiOD · D₂O. The temperature dependence of the quadrupole coupling constant of the OD^– ion is governed by its torsional modes; in the neutron inelastic scattering spectra these appear near 642 cm^–1 in LiOH · H₂O and 468 cm ^–1 in LiOD · D₂O.