Conditions of stability for (Li2CO3Â +Â Li2O) melts in air

► The equilibrium pressure of CO2 was measured above (Li2CO3 + Li2O) melts. ► The enthalpy and entropy of decomposition of Li2CO3 are constant for mole fraction of lithium oxide (0.02 to 0.06). ► Conditions under which the melts are in equilibrium with atmospheric CO2 were demonstrated. ► Stability of the melt is attributed to reduction of the equilibrium pressure of CO2 due to Li2O formation.