The diffusivity and solubility of fluorine in solid nickel were determined using the following solid-state electrochemical cells: Co + CoF2| BaF2| Ni | BaF2| Co + CoF2 Co + CoF2| CaF2| BaF2| Ni | BaF2| CaF2| Co + CoF2 In the temperature range 1023 to 1223 K, the diffusion coefficient of fluorine in solid nickel is given by: 1 $$D_F (cm^2 /s) = (2.13_{ - 1.54}^{ + 5.54} ) \times 10^{ - 3} \exp (( - 118,600 \pm 12,000J/mol)/RT)$$ The dissolution of atomic fluorine in solid nickel obeys Sieverts’ law; however, the solubility results showed considerable scatter. In the temperature range 1073 to 1223 K, the mean solubility of fluorine in solid nickel, corresponding to the equilibrium Ni + NiF2, follows the relationship: N -F S (at. pct) = 5.73 x 10-3 exp((10,850 J/mol)/RT)