²³Na NMR study of the mobile sodium in Na β gallate

Measurements of the nuclear relaxation time T1, the quadrupole coupling constant and the second order quadrupole shift of 23Na in single crystals of Na β gallate are reported. The quadrupolar coupling constant is 0.981±0.005 MHz at 395°C. The second order quadrupole shift is temperature dependent and gives evidence for changes in the site occupancy as the temperature is varied. The relaxation time has a weakly frequency dependent minimum above room temperature. It is clear that like Na β Al2O3 the relaxation behaviour cannot be described by a single exponential correlation function. Below room temperature more than one line is observed giving further evidence for site occupancy changes. © 1983.