The common oxidation number for an alkaline earth metal is +2. Using the Born–Mayer equation and a Born–Haber cycle, show that CaCl is an exothermic compound. Use a suitable analogy to estimate an ionic radius for Ca+. The sublimation enthalpy of Ca(s) is 176 kJmol-1. Show that an explanation for the nonexistence of CaCl can be found in the enthalpy change for
the reaction 2 CaCl(s) → Ca(s) + CaCl2(s).
Then ΔHf= < 0 - an exothermic process
Thus we show that CaCl is an exothermic compound.
for the reaction 2 CaCl(s) → Ca(s) + CaCl2(s).
- exotermic. Thus nonexistent CaCl would decompose spontaneously to CaCl2 and Ca.