Definition of the BF3 Affinity Scale

The formation of the 1 1 complex between BF3 and a Lewis base, LB, can be written as 

By far the most important body of data on the thermodynamics of this reaction has been provided by the group of Gal and Maria at the University of Nice-Sophia Antipolis. For technical reasons, these authors chose to study reaction 3.5 between gaseous BF3 and the Lewis base in a dilute solution of dichloromethane at 298 K. The affinity scale can be defined as the negative enthalpy of reaction 3.6  

BFsCg) + LB(CH2Cl2 solution) LB-BF3(CH2Cl2 solution) BF3A = -AH°(3.6) 

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