A Gibbs energy minimization model capable of predicting the simultaneous NH3 synthesis and absorption equilibrium has been developed, validated and applied to study the thermodynamic potential of sorption-enhanced NH3 synthesis using MgCl2 as a sorbent. Therefor, the standard Gibbs energy of formation of the loaded sorbent, MgCl2⋅NH3, has been obtained by data fitting to the sorption equilibrium. The thermodynamic analysis revealed that sorption enhancement using MgCl2 significantly shifts the NH3 synthesis equilibrium towards higher conversion and allows for near full conversion under a wide range of operating conditions, including moderate pressures and temperatures high enough for sufficient reaction rates.