 The atomization energy of KrF2 (KrF2(g) → Kr(g) + 2F(g)) is 21.9 kcal/mol, giving an average Kr–F bond energy of only 11 kcal/mol, the weakest of any isolable fluoride.In comparison, difluorine is held together by a bond of 36 kcal/mol.Consequently, KrF2 is a good source of the extremely reactive and oxidizing atomic fluorine.