Born-Haber dataa for alkali halides, in kJ/mole

 

 

Li

Na

K

Rb

Cs

 

DHa,m = 161

107.7

89.1

85.8

76.6

 

DHion = 520.1

495.8

418.8

403.0

375.7

F

DHea = 327.9

DHf = -616.9

-569.0

-562.6

-549.3

-530.9

 

DHa,n = 78.5

DHxtal = -1,049

-923.1

-821.1

-788.7

-733.8

Cl

DHea = 348.6

DHf = -408.8

-411.0

-435.9

-430.5

-433.0

 

DHa,n = 121.3

DHxtal = -863

-787.2

-716.5

-692.0

-658.0

Br

DHea = 324.4

DH f = -350.3

-359.9

-392.2

-389.2

-394.6

 

DHa,n = 11.9

DH xtal = -819

-750.9

-687.6

-665.5

-634.4

I

DHea = 295.3

DH f = -297.9

-288.0

-327.6

-328.4

-336.8

 

DHa,n = 106.8

DH xtal = -790

-703.0

-647.0

-628.7

-600.6

aAll values of DHion and DHea are for 0 K, that is, about 6 kJ less than the values at 25C.  These two differences cancel one another in the Born-Haber cycle calculations.