Bond Dissociation Energies (kcal/mol)

(X-Y -----> X . + Y . )

DHo (RH) = ΔHfo (R.) + ΔHfo (H.) - ΔHfo (RH)

Values are taken from Blanksby and Ellison, Acc. Chem. Res. 2003, 36, 255. They have been rounded to the nearest whole number. Errors in measurement may make values appear out of order, e.g., C-Br. The Ellison paper is here in pdf format. Older, but acceptable, values in parentheses are summarized in McMillen and Golden, Annu. Rev. Phys. Chem. 1982, 33, 493. Loudon's text uses the Ellison values. For a table of heats of formation click here. For a discussion on the relationship between BDEs and heats of formation, click here.

C-H Bonds

CH3-H

CH3CH2-H

(CH3)2CH-H

(CH3)3C-H

CH2=CHCH2-H

PhCH2-H

CH2=CH-H

C6H5-H

HCC-H

105

101

99

97

89

90

110

113

133

C-C Bonds

CH3-CH3

CH3CH2-CH3

(CH3)2CH-CH3

CH3CH2-CH2CH3

(CH3)3C-CH3

90

89

89

88

88

C-F Bonds

CH3-F

CH3CH2-F

(CH3)2CH-F

(CH3)3C-F

115

-

111

-

C-Cl Bonds

CH3-Cl

CH3CH2-Cl

(CH3)2CH-Cl

(CH3)3C-Cl

84

85

85

85

C-Br Bonds

CH3-Br

CH3CH2-Br

(CH3)2CH-Br

(CH3)3C-Br

72

72

74

73

C-I Bonds

CH3-I

CH3CH2 -I

(CH3)2CH-I

(CH3)3C-I

58

57

57

56

H-X Bonds

H-F

H-Cl

H-Br

H-I

H-H

HO-H

HOO-H

H2N-H

136

103

88

71

104

119

88

108

X-X Bonds

F-F

Cl-Cl

Br-Br

I-I

HO-OH

(36)

(58)

(46)

(36)

(51)