Electrical and diffusion properties of two complementary series of ZrF 4 -based fluoride glasses containing LiF were examined as a function of LiF content (0 ≤ x L i F ≤ 0.60). The ac conductivity data have been analyzed by the complex modulus formalism and a hopping mechanism for transport is suggested. Experimental points representative of various electrical and diffusion parameters as a function of x L i F for the glasses studied are located on both sides of 'master' curves, 1 9 F and Li 7 i NMR investigations show that F - and Li + ions participate as charge carriers in the conduction mechanisms. The variation of electrical and diffusion properties with increasing x L i F have been explained by the crossing for x L i F ≃ 0.20 from a conductivity due preferentially to F - ions to a conductivity due preferentially to Li + ions. A minimum of the decoupling index, R τ (T g ), is shown for x L i F ≃ 0.20, in agreement with the conductivity minimum observed for the same x L i F content. Variation of the β conductivity relaxation parameter involves a minimum for x L i F ≃ 0.35. A structural origin is proposed for such a minimum, the existence of which has been previously shown for x N b F ≃ 0.40 in the homologous fluoride glasses containing NaF.