Aqueous Ni II - iodo complexes

No quantitative data are available for the formation of Nil complexes. The formation of Nir and Nil2(aq) vcas postulated in [74KUT/GAL], to explain the polarographic prewaves of Ni(II) reduction in 5 M Ca(N03)2 solutions containing 0.2 - 1 M KI. The spec-trophotometric data reported in [68AND/KHA2] indicate formation of a considerable amount of Nil in 9 - 11 M HI solutions (see Appendix A). 

According to the specific ion-interaction theory the mean activity coefficient of Ni(C104)2 can be expressed as (V.74)  

In [69LIB/SAD] the osmotic coefficients have been determined by the isopi-estic method. 

The mean value of the entirely independent investigations (emf measurements [99MAL/CAR] and isopiestic measurements [69LIB/SAD]) is selected  

The uncertainty is rather pessimistic but takes into account that the weighting scheme influences the numerical value of (Ni , CIO4) considerably. 

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