Proton affinity (data page)

Proton affinities are quoted in kJ/mol, in increasing order of gas-phase basicity of the base.

Base	Proton affinity (kJ/mol)
Neutral molecules
Helium	178
Neon	201
Argon	371
Dioxygen	422
Dihydrogen	424
Krypton	425
Hydrogen fluoride	490
Dinitrogen	495
Xenon	496
Nitric oxide	531
Carbon dioxide	548
Methane	552
Hydrogen chloride	564
Hydrogen bromide	569
Nitrous oxide	571
Carbon monoxide	594
Ethane	601
Nitrogen trifluoride	602
Hydrogen iodide	628
Carbonyl sulfide	632
Acetylene	641
Arsenic trifluoride	649
Silane	649
Sulfur dioxide	676
Hydrogen peroxide	678
Ethylene	680
Phosphorus trifluoride	697
Water	697
Carbon disulfide	699
Phosphoryl trifluoride	702
2,4-Dicarba-closo-heptaborane(7)	703
Hydrogen sulfide	712
Hydrogen selenide	717
Hydrogen cyanide	717
Formaldehyde	718
Carbon monosulfide	732
Cyanogen chloride	735
Arsine	750
Benzene	759
Methanol	761
Methanethiol	784
Ethanol	788
Acetonitrile	788
Phosphine	789
Nitrogen trichloride	791
Ethanethiol	798
Propanol	798
Propane-1-thiol	802
Hydroxylamine	803
Dimethyl ether	804
Glyceryl phosphite	812
Borazine	812
Acetone	823
Diethyl ether	838
Dimethyl sulfide	839
Iron pentacarbonyl	845
Ammonia	854
Methylphosphine	854
Hydrazine	856
Diethyl sulfide	858
1,6-Dicarba-closo-hexaborane(6)	866
Aniline	877
P(OCH₂)₃CCH₃	877
Ferrocene	877
Dimethyl sulfoxide	884
Dimethyl formamide	884
Trimethyl phosphate	887
Trimethylarsine	893
Methylamine	896
Tri-O-methyl thiophosphate	897
Dimethylphosphine	905
Trimethyl phosphite	923
Dimethylamine	923
Pyridine	924
Trimethylamine	942
Trimethylphosphine	950
Triethylphosphine	969
Triethylamine	972
Lithium hydroxide	1008
Sodium hydroxide	1038
Potassium hydroxide	1100
Caesium hydroxide	1125
Anions
Trioxophosphate(1−)	1301
Iodide	1315
Pentacarbonylmanganate(1−)	1326
Trifluoroacetate	1350
Bromide	1354
Nitrate	1358
Pentacarbonylrhenate(1−)	1389
Chloride	1395
Nitrite	1415
Hydroselenide	1417
Formate	1444
Acetate	1458
Phenoxide	1470
Cyanide	1477
Hydrosulfide	1477
Cyclopentadienide	1490
Ethanethiolate	1495
Nitromethanide	1501
Arsinide	1502
Methanethiolate	1502
Germanide	1509
Trichloromethanide	1515
Formylmethanide	1533
Methylsulfonylmethanide	1534
Anilide	1536
Acetonide	1543
Phosphinide	1550
Silanide	1554
Fluoride	1554
Cyanomethanide	1557
Propoxide	1568
Acetylide	1571
Trifluoromethanide	1572
Ethoxide	1574
Phenylmethanide	1586
Methoxide	1587
Hydroxide	1635
Amide	1672
Hydride	1675
Methanide	1743

Source: Jolly, William L. (1991). Modern Inorganic Chemistry (2nd Edn.). New York: McGraw-Hill. ISBN 0-07-112651-1.