MgO(s) has the same crystal structure as NaCl(s). The experimental lattice enthalpy of NaCl(s) is −781 kJ mol-1 whilst that of MgO(s) is -3889 kJ mol-¹. The corresponding theoretical values are -777 kJ mol-1 and -3791 kJ mol-1. Explain as fully as possible on the differences between the experimental and theoretical lattice enthalpies for these two compounds
