Aqueous nickel borato complexes

The existence of at least one soluble nickel borate complex was postulated by Shchigol [61SHC]. Nickel orthoborate Ni(B02)2 4H20(s) dissolves better in orthoboric acid solutions than in pure water. The formation of the nickel borate complex in solution was believed to occur according to the reaction  

The dissociation constant of the aqueous nickel borate complex, according to Reaction (V.125), was calculated by Shchigol [61SHC], ) 3, (V.125) = 2.82x10 mol dm . 

An inspection of the experimental data revealed that they were misinterpreted, although Equation (V.124) may be correct, see Appendix A. Consequently the reported value of the dissociation constant was not selected by the present reviewers. 

---