Bjerrum’s association constant

Figure 3 shows the family tree of some association constants which can be found in the literature and indicates the presuppositions for deducing them from the initial equation. For example, Bjerrum s association constant and its appropriate activity coefficient are obtained from Eqs. (19) by setting R = q and = 0. As a further... 

Perhaps the greatest uncertainty in the evaluation is caused by the selection of the appropriate ionic radii, / . In accordance with the introduction of Bjerrum s association constant [Bj 26], Justice [Ju 71b, Ju 75a, Ju 75b] assumes the equation Ry = R = q From chemical considerations, Barthel [Ba 78a] considers it more correct to describe the radius Ry as the sum of the contact distance, a, of the ions and the size, s, of the solvent molecule Xy=a4-s. 

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