A new series of fluoride glasses of formulation ZrF4(0.25)-ZnF2(0.15)-YF3(0.05)-AlF3(0.10)-CdF2(0.17 - 2x/5)-BaF2(0.28 - 3x/5)-LiF(x) and containing a wide LiF concentration range (0 less than or equal to x(LiF) less than or equal to 0.35) has been investigated by impedance spectroscopy : the variation of various electrical parameters has been determined as a function of composition. The results obtained with two other series of fluoride glasses covering the (0 less than or equal to x(LiF) less than or equal to 0.30) and (0.20 less than or equal to x(LiF) less than or equal to 0.60) concentration ranges are confirmed. A conductivity minimum associated with an activation energy maximum and a minimum of the decoupling index R-tau(T-g) takes place for x(LiF) similar or equal to 0.20. It is explained by the crossing with increasing x from a conductivity due preferentially to F- ions to a conductivity due preferentially to Li+ ions. Within each series, the composition relative to conductivity minimum offers a value r similar or equal to 1 of the (x(LiF)/x(BaF2)) ratio. For higher x(LiF) rates, the beta conductivity relaxation parameter involves also a minimum. Comparison of various series studied indicates that the composition relative to beta minimum offers a value r similar or equal to 2 of the (x(LiF)/x(BaF2)) ratio. The structural origin of the beta minimum is confirmed.