Introduction

Although electronegativity according to its original definition by Pauling is a property of an element it is such a useful concept that attempts have been made to apply it to functional groups as well. The electronegativity of functional groups can be estimated using a number of different approaches. The values shown here are computed using the assumption of electronegativity equalization. A key feature of group electronegativities is that they are not constant but vary depending on their surrounding.
They can be seen as a complement to Hammett-type parameters when describing functional group polarity but are less versatile.

1. J.E. Huheey, J. Phys. Chem. 69 (1965) 3284-3291, J. Phys. Chem. 70 (1966) 2086-2092
2. S.G. Bratsch, J. Chem. Edu. 62 (1985) 101-103

Group electronegativities by different methods

Name	Symbol	Huheey (1965, -66)	Bratsch (1985)
1,1-difluoroethyl‐	‐CF2CH3	2.9
2,4,6-tribromophenyl‐	‐C6H2Br3	2.61
2,4,6-trichlorophenyl‐	‐C6H2Cl3	2.71
2,4,6-trichlorostyryl‐	‐CH=CHC6H2Cl3	2.65
2,4,6-trifluorophenyl‐	‐C6H2F3	2.89
2,4,6-triiodophenyl‐	‐C6H2I3	2.57
2,4,6-trimethylstyryl‐	‐CH=CHC6H2(CH3)3	2.41
2,4,6-trinitrophenyl‐	‐C6H2(NO2)3	3.68
2,4,6-trinitrostyryl‐	‐CH=CHC6H2(NO2)3	3.56
3,5-dibromophenyl‐	‐C6H3Br2	2.57
3,5-dichlorophenyl‐	‐C6H3Cl2	2.64
3,5-dichlorostyryl‐	‐CH=CHC6H3Cl2	2.59
3,5-difluorophenyl‐	‐C6H3F2	2.75
3,5-diiodophenyl‐	‐C6H3I2	2.55
3,5-dimethylstyryl‐	‐CH=CHC6H3(CH3)2	2.43
3,5-dinitrophenyl‐	‐C6H3(NO2)2	3.36
3,5-dinitrostyryl‐	‐CH=CHC6H3(NO2)2	3.16
acetoxy‐	‐OCOCH3	2.95	2.56
acetyl‐	‐COCH3	2.69	2.46
allyl‐	‐CH2CH=CH2	2.37
amino‐	‐NH2	2.61	2.42
azido‐	‐N3	4.42	3.04
benzenesulfinyl‐	‐S(=O)C6H5	2.7
benzenesulfonyl‐	‐S(=O)2C6H5	2.9
beryllanyl‐	‐BeH	1.89
boranyl‐	‐BH2	2.09
bromoberyllanyl‐	‐BeBr	1.94
bromochlorofluoromethyl‐	‐CBrClF	2.9
bromochloroiodomethyl‐	‐CBrClI	2.64
bromochloromethyl‐	‐CHBrCl	2.58
bromoiodomethyl‐	‐CHBrI	2.47
bromomagnesanyl‐	‐MgBr	1.73
bromomethyl‐	‐CH2Br	2.4
bromoxy‐	‐OBr	3.4
bromyloxy‐	‐OBrO2		3.31
carboxy‐	‐COOH	3.49	2.8
chloroberyllanyl‐	‐BeCl	2.02
chlorofluoromethyl‐	‐CHClF	2.82
chloromagnesanyl‐	‐MgCl	1.79
chloromethyl‐	‐CH2Cl	2.47
chlorosyloxy‐	‐OClO	4.6	3.34
chloroxy‐	‐OCl	3.73	3.29
chloroxy‐	‐OCl	4.4	3.29
chloryloxy‐	‐OClO2	4.8	3.37
cyanato‐	‐OCN	4.66	2.97
cyano‐	‐CN	3.84	2.77
di(trifluoromethyl)methyl‐	‐CH(CF3)2	3.19
dibromoboranyl‐	‐BBr2	2.38
dibromomethyl‐	‐CHBr2	2.5
dibromophosphino‐	‐PBr2	2.56
dibromophosphoryl‐	‐P(=O)Br2	3.1
dichloroamino‐	‐NCl2	3.14
dichloroboranyl‐	‐BCl2	2.55
dichloromethyl‐	‐CHCl2	2.66
dichlorophosphino‐	‐PCl2	2.71
dichlorophosphoryl‐	‐P(=O)Cl2	3.3
diethylamino‐	‐N(CH2CH3)2	2.36
diethylphosphino‐	‐P(CH2CH3)2	2.29
difluoroamino‐	‐NF2	3.64	3.61
difluoroboranyl‐	‐BF2	2.92
difluoromethyl‐	‐CHF2	3
difluorophosphino‐	‐PF2	3.29
difluorophosphoryl‐	‐P(=O)F2	3.8
dihydroxyphosphoryl‐	‐P(=O)(OH)2	3.6
diiodoboranyl‐	‐BI2	2.3
diiodomethyl‐	‐CHI2	2.44
dimethylamino‐	‐N(CH3)2	2.4
dimethylboranyl‐	‐B(CH3)2	2.23
dimethylphosphino‐	‐P(CH3)2	2.28
ethoxy‐	‐OCH2CH3	2.53
ethyl‐	‐CH2CH3	2.27	2.29
ethylamino‐	‐NHCH2CH3	2.4
ethylsulfanyl‐	‐SCH2CH3	2.39
ethynyl‐	‐C≡CH	2.9
fluoroberyllanyl‐	‐BeF	2.16
fluorohydroxy‐	‐OF	4.14
fluoromagnesanyl‐	‐MgF	1.87
fluoromethyl‐	‐CH2F	2.61
formyl‐	‐CHO	3.14	2.64
formyloxy‐	‐OCHO	3.54	2.8
germanyl‐	‐GeH3	2.32
hydrazino‐	‐NHNH2	2.63
hydroxamino‐	‐NHOH	3.16
hydroxy‐	‐OH	3.51	2.68
hydroxymethyl‐	‐CH2OH	2.74
iodoberyllanyl‐	‐BeI	1.91
iodomagnesanyl‐	‐MgI	1.7
iodomethyl‐	‐CH2I	2.37
iodyloxy‐	‐OIO2		3.21
isocyanato‐	‐NCO	4.46	2.97
isopropyl‐	‐CH(CH3)2	2.28
isothiocyanato‐	‐NCS	4.17	2.71
magnesanyl‐	‐MgH	1.5
mercapto‐	‐SH	2.32	2.37
methoxy‐	‐OCH3	2.68	2.44
methoxycarbonyl‐	‐COOCH3	2.94
methyl‐	‐CH3	2.27	2.28
methylamino‐	‐NHCH3	2.45
methylberyllanyl‐	‐BeCH3	2.01
methylmagnesanyl‐	‐MgCH3	1.88
methylsulfanyl‐	‐SCH3	2.45
methylsulfinyl‐	‐S(=O)CH3	2.8
methylsulfonyl‐	‐S(=O)2CH3	3.1
nitro‐	‐NO2	4.58	3.3
nitrooxy‐	‐ONO2	4.58	3.33
nitroso‐	‐NO	4.45	3.23
nitrosooxy‐	‐ONO	4.43	3.3
p-bromophenyl‐	‐C6H4Br	2.53
p-chlorophenyl‐	‐C6H4Cl	2.56
p-chlorostyryl‐	‐CH=CHC6H4Cl	2.54
p-fluorophenyl‐	‐C6H4F	2.55
p-hydroxyphenyl‐	‐C6H4OH	2.68
p-iodophenyl‐	‐C6H4I	2.52
p-methylstyryl‐	‐CH=CHC6H4CH3	2.45
p-nitrophenyl‐	‐C6H4NO2	2.98
p-nitrostyryl‐	‐CH=CHC6H4NO2	2.85
pentamethylphenyl‐	‐C6(CH3)5	2.37
pentamethylstyryl‐	‐CH=CHC6(CH3)5	2.38
perchloryloxy‐	‐OClO3		3.38
perfluoroethyl‐	‐CF2CF3	3.4
perfluoroisopropyl‐	‐CF(CF3)2	3.38
phenoxy‐	‐OC6H5		2.44
phenyl‐	‐C6H5	2.49	2.38
phosphino‐	‐PH2	2.13	2.2
phosphoroso‐	‐PO	3.8
silyl‐	‐SiH3	2.21	2.12
stannyl‐	‐SnH3	2.32
styryl‐	‐CH=CHC6H5	2.48
thiocyanato‐	‐SCN	3.91	2.71
tribromogermanyl‐	‐GeBr3	2.58
tribromomethyl‐	‐CBr3	2.59
tribromosilyl‐	‐SiBr3	2.54
tribromostannyl‐	‐SnBr3	2.55
trichlorogermanyl‐	‐GeCl3	2.79
trichloromethyl‐	‐CCl3	2.84	2.98
trichlorosilyl‐	‐SiCl3	2.78
trichlorostannyl‐	‐SnCl3	2.73
trifluorogermanyl‐	‐GeF3	3.25
trifluoromethoxy‐	‐OCF3	3.74
trifluoromethyl‐	‐CF3	3.46	3.49
trifluorosilyl‐	‐SiF3	3.35	3.12
trifluorostannyl‐	‐SnF3	3.11
triiodogermanyl‐	‐GeI3	2.51
triiodomethyl‐	‐CI3	2.51
triiodosilyl‐	‐SiI3	2.46
triiodostannyl‐	‐SnI3	2.49
trimethylgermanyl‐	‐Ge(CH3)3	2.19
trimethylsilyl‐	‐Si(CH3)3	2.27
trimethylstannyl‐	‐Sn(CH3)3	2.3
vinyl‐	‐CH=CH2	2.41