The self-diffusion coefficients of F in the melt were measured by using the capillary reservoir technique, with 18F as a tracer. It was found that the results (table 165) could be described by:

D (cm2/s) = 6.53 x 103 exp[-30.6(kcal/mol)/RT]

The high activation energy for F self-diffusion was explained in terms of the F transport that resulted from the movement of fluoroberyllate anions, exchange of F between neighboring anions, and ion-pair diffusion.

Self-Diffusion of Fluorine in Molten Dilithium Tetrafluoroberyllate. T.Ohmichi, H.Ohno, K.Furukawa: Journal of Physical Chemistry, 1976, 80[14], 1628-31