Solvent polarity acc. Dimroth and Reichardt

Dimroth and Reichardt determined the wavenumber of the absorption maximum for a betain dye as a measure of the ionizing power of solvents. It is converted to kcal/mol (2.86x10⁴λ^-1) to give E_T.
Normalizing to a scale from TMS (0) to water (1) gives E_T^N.
See e.g. IUPAC Gold Book.

Dimroth's E_T values
Name	CAS nr	E_T	E_T^N
2-propanone	67-64-1	42.2	0.35
4-methyl-2-oxo-1,3-dioxolane	108-32-7	46.6	0.49
acetonitrile	75-05-8	45.6	0.46
benzonitrile	100-47-0	41.5	0.33
butanenitrile	109-74-0	43.1	0.38
butanol	71-36-3	50.2	0.60
dimethyl sulfoxide	67-68-5	45.1	0.44
ethanol	64-17-5	51.9	0.65
formamide	75-12-7	56.6	0.80
hexamethylphosphoramide	680-31-9	40.9	0.31
methanol	67-56-1	55.4	0.76
N,N,N',N'-tetramethylurea	632-22-4	41.0	0.32
N,N-dimethylacetamide	127-19-5	43.7	0.40
N,N-dimethylformamide	68-12-2	43.8	0.40
N-methylformamide	123-39-7	54.1	0.72
N-methylpyrrolidone	872-50-4	42.2	0.35
nitrobenzene	98-95-3	41.2	0.32
nitromethane	75-52-5	46.3	0.48
propanol	71-23-8	50.7	0.62
sulfolane	126-33-0	44.0	0.41
water	7732-18-5	63.1	1.00

Tables for Chemistry

Solvent polarity acc. Dimroth and Reichardt