The heat capacities of MgO, CaO, SrO, BaO, having NaCl-structure, have been measured with an adiabatic calorimeter capable to measure heat capacities of solids between 1.2 and 340 ºK. A mechanical thermal switch is used for specimen cooling and the temperature calibration above 4 ºK is performed with a gas thermometer.
The values of the specific heats, Cp, are tabulated. The entropies at 273.15 ºK are 27.19; 38.3; 51.9; and 66.9 for MgO, CaO, SrO and BaO respectively, in J/mol ºK. The accuracy of the measurements is estimated to be better than 0.8% (smoothed curve).