Question

Consider an ionic compound, MX2, composed of generic metal M and generic, gaseous halogen X.

The enthalpy of formation of MX2 is ΔHf° = –883 kJ/mol. The enthalpy of sublimation of M is ΔHsub = 123 kJ/mol. The first and second ionization energies of M are IE1 = 665 kJ/mol and IE2 = 1397 kJ/mol. The electron affinity of X is ΔHEA = –313 kJ/mol. (Refer to the Hint). The bond energy of X2 is BE = 157 kJ/mol.

Determine the lattice energy of MX2.

_____KJ/mol