Known findings on thermodynamic properties of molten magnesium and alkaline-earth alloys have been classified. Empiric equations are derived on the strength of most reliable values of extra partial-molar entropy and enthalpy for alkaline-earth metals in diluted solutions and from data on phase compositions. These empiric equations which generalize the findings obtained are useful for the estimation and development of theoretical models. A satisfactory correlation and considerable discrepancy between predicted and experimental data are explained.