Answer :  The magnitude of the lattice energy for CsCl is, 667 KJ/mole
Explanation : 
The steps involved in the born-Haber cycle for the formation of  :
 :
(1) Conversion of solid calcium into gaseous cesium atoms.

 = sublimation energy of calcium
 = sublimation energy of calcium
(2) Conversion of gaseous cesium atoms into gaseous cesium ions.

 = ionization energy of calcium
 = ionization energy of calcium
(3) Conversion of molecular gaseous chlorine into gaseous chlorine atoms.

 = dissociation energy of chlorine
 = dissociation energy of chlorine
(4) Conversion of gaseous chlorine atoms into gaseous chlorine ions.

 = electron affinity energy of chlorine
 = electron affinity energy of chlorine
(5) Conversion of gaseous cations and gaseous anion into solid cesium chloride.

 = lattice energy of calcium chloride
 = lattice energy of calcium chloride
To calculate the overall energy from the born-Haber cycle, the equation used will be:

Now put all the given values in this equation, we get:


The negative sign indicates that for exothermic reaction, the lattice energy will be negative.
Therefore, the magnitude of the lattice energy for CsCl is, 667 KJ/mole