In chemistry a donor number or DN is a qualitative measure of lewis basicity. A donor number is defined as the negative enthalpy value for the 1:1 adduct formation between a lewis base and the standard Lewis acid SbCl₅ or antimony pentachloride, in dilute solution in the noncoordinating solvent 1,2-dichloroethane with a zero DN. The units are kcal per mole for historical reasons . The donor number is a measure of the ability of a solvent to solvatate cations and lewis acids The method was developed by V. Gutmann in 1976 . Likewise lewis acids are characterized by acceptor numbers.

Typical solvent values are:

• acetonitrile 14.1
• acetone 17
• methanol 19
• DMF 26.6
• DMSO 29.8
• ethanol 31.5
• triethylamine 61

External links

• Gold Book Definition

References

• Critical evaluation of stability constants and thermodynamic functions of metal complexes of crown ethers Françoise Arnaud-neu, Rita Delgado, and Sílvia Chaves Pure Appl. Chem., Vol. 75, No. 1, pp. 71–102, 2003. Article
• V. Gutmann, Coord. Chem. Rev., 19 (1976) 225

chemical bonding