The enthalpy of formation of MX is ΔHf° = –525 kJ/mol. The enthalpy of sublimation of M is ΔHsub = 139 kJ/mol. The ionization energy of M is IE = 437 kJ/mol. The electron affinity of X is ΔHEA = –313 kJ/mol. (Refer to the hint). The bond energy of X2 is BE = 227 kJ/mol.
