What is the enthalpy change when one mole of crystal lattice is formed from the isolated gaseous ions?
The above value corresponds to the value of the enthalpy of formation of the crystal lattice. Its establishing by experimental method is not possible, but it can be calculated based on the Born-Haber cycle looks like enthalphy. Also, the corresponding values can be calculated from knowing enthalpy of the crystal lattice and the temperature of crystal formation process. Enthalpy change during the formation of the crystal lattice of the ion gas is always greater than 0.