carboxylic acid
2.5-5
b-dicarbonyl
4.5-8.5
sulfonamides
4.5-11.5
sulfonylureas
5-6
tetrazole
4.5-6
phenol
9-10
sulfates
1-2
phosphates
1st H: 1.5-2.5
2nd H: 6.5-7.5
aliphatic & alicyclic amines
9-10
aromatic amines
2-5
imines
3-5
hydrazines
7.5-8.5
amidines
10-11
guanidines
12-13
aromatic heterocyclic N atoms
1-5