The electrical conductivities of molten , , , , and were measured by electrochemical impedance spectroscopy. A new conductance cell was designed and constructed for the purpose of determining the electrical properties of highly conductive and very corrosive melts at temperatures as high as 1600°C. The cell is comprised of twin capillaries of pyrolytic boron nitride, long, two movable tungsten electrodes, and a molybdenum crucible. The ranking by specific electrical conductivity, κ, was and by molar electrical conductivity, , was . was found to vary with the logarithm of the charge density of the metal cation over the entire series of alkaline‐earth fluorides. With the exception of , was found to vary with , where is the molar volume and is the coulombic energy between nearest neighbor ions in the melt.