A Values

Energy Differences Between Equatorial and Axial Monosubstituted Cyclohexanes

 

X Group
ΔGo (axial-equatorial) [kcal/mole]
ΔGo (axial-equatorial) [kJ/mole]
-CN
0.2
0.8
-F
0.2
0.8
-Cl
0.5
2.1
-Br
0.6
2.5
-CHO
0.6
2.5
-OH
1.0
4.1
-COOH
1.4
5.9
-CH3
1.8
7.6
CH2CH3
1.9
7.9
-CH(CH3)2
2.1
8.8
-C(CH3)3
5.4
23
-CO2CH3
1.2
5.0
-CCH
0.4
1.7
-SiH3
1.5
6.0
-Si(CH3)3
2.5
10.5
-Sn(CH3)3
1.0
4.2
-C6H5
2.8
11.7
-N3
0.5
2.1
-OCH3
0.6
2.5

Free energy: ΔGo=-RTlnKeq at 298 oC or -1.38log10Keq. Keq=x/(1-x) where x = the mole fraction of the axial component and 1-x is the equatorial mole fraction.