Definition of the Donor Number Scale

The formation of the 1 1 complex B-SbCls at 298 K in a dilute solution of 1,2-dichloroethane can be written 

The donor number (DN), or donicity, of the Lewis base was defined [16-18] as the negative enthalpy (in kcal mor ) of this reaction  

In the terminology of this book, DN is the SbCb affinity, denoted SbClsA. 

For solubility reasons, the SbCls complexation could not be accomplished in a less polar solvent. For example, the complexes of the following bases were not soluble enough in CCI4 dimethyl sulfoxide, dimethylacetamide, tetramethylurea, trihexylamine and octylamine 

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