where ∆ν(T) is the linewidth at temperature T, and ∆νR is the linewidth in the rigid-lattice regime. B is the linewidth that would be obtained at extreme narrowing in the absence of magnetic field inhomogeneity and D is a correction factor accounting for broadening arising from the inhomogeneity of the static magnetic field. From this model we obtain an activation energy of 0.21±0.01 eV for lithium diffusion in LNCl. The value of B is an indicator for the 'range' of motion. The larger B, the more 'short-range' the motion because locally confined motion is not expected to entirely eliminate dipole-dipole interactions. For different ion conductors values for B ranged from 10 -3 to 10 -13 kHz. The value of B obtained for LNCl (5•10 -4 kHz) thus suggests that the line-narrowing is caused by locally confined motion. To what range exactly this motion may be confined, goes beyond the predictive scope of the Hendrickson-Bray equation.