The phase diagram of the CaCl2CaH2 system was investigated by using a differential scanning calorimeter and is reported. The hydride-ion conducting compound, CaHCI, is found to be peritectically melting. The total conductivity of CaCl2-5 mol% CaH2 solid electrolyte was measured by impedance spectroscopy and the electronic conductivity was determined by the DC polarisation technique in the temperature range of 673 to 796 K and hydrogen pressure range of 0.03-5 Pa. The activation energy for the ionic conduction was found to be 1.02 eV. © 1995.