CATION DYNAMICS AND DIFFUSION IN LITHIUM ORTHOSILICATE - 2-DIMENSIONAL LI-6 NMR

Many geological and technological processes depend on diffusion in cry stalline silicates and oxides, but models of the dynamics of diffusion have only rarely been based on relatively direct microscopic informat ion on the rates and energetics of the hopping of cations from site to site. Two-dimensional nuclear magnetic resonance (NMR) exchange spect ra for lithium-6 in lithium orthosilicate (Li(4)SiO4) provided a detai led picture of the hopping rates of Li+ ions among structurally distin ct sites and helped to define the diffusion pathway. Rates and activat ion energies depended measurably on site geometry, and bulk electrical conductivity was accurately predicted.