A comprehensive experimental and theoretical NMR study of two diffusion processes in Li3N is presented: interlayer diffusion parallel to the hexagonal axis involving both Li sites and intralayer diffusion within the Li2N layers only. The first process allows a quantitative and consistent analysis of the following NMR observables: (i) the second-order quadrupolar shift of the 'Li central signal and its strong temperature dependence between 400 and 600 K, and (ii) the temperature dependence (above 420 K) and the extreme angle dependence of the Li and Li relaxation rates by taking into account different relaxation mechanisms for both isotopes. The activation energy (0.62 eV) and the correlation times agree with values deduced from conductivity measurements.The intralayer diffusion process is studied by means of the temperature and angle dependence of Li and Li relaxation times below 320 K. The Li(2) vacancy concentration is determined in agreement with x-ray data.

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Quadrupole split NMR-spectra of 7Li and 14N in single crystals of Li3N were measured as a function of orientation to the magnetic field. The results confirm the model of ionic bonding. From the temperature dependence of both the 7Li spectra and the relaxation rate Ɖ1 of 7Li at least two diffusion processes could be determined which are in agreement with the strong anisotropy of the ionic conductivity. Below 300 K nearly all diffusion takes place in the Li2N layer with an activation enthalpy of about 0.25 eV. The jump rate of the ions can be increased by doping the crystals with hydrogen. At higher temperatures there is a considerable amount of interplanar diffusion involving both Li positions

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