Cesium chlorides is formed according to the following equation Cs(s)+0.5 Cl2(g)→CsCl(s). The enthalpy of sublimation of Cs, the enthalpy of dissociation of chlorine, ionization energy of Cs and electron affinity of cholrine are 81.2,243.0,375.7 and −348.3 kJ mol−1. The energy involved in the formation of CsCl is −388.6 kJ mol−1. Calculate the lattice energy of CsCl.
⇒△Hf=△Hs+I.E+△Hd2+E.A+L
⇒L=−388.6–81.2−243.02–375.7+348.3
=−618.7 kJ/mol