Ionization equilibria of nickel(II) bromide in acetonitrile solutions

Abstract Uv and visible absorption spectra and the molar conductance curve of NiBr 2 in acetonitrile solution have been determined at 25°C. Equilibrium concentrations and formation constants of the consecutive NiBr + , NiBr 0 2 , and NiBr − 3 , complexes have been calculated from the spectrophotometric results making use of the isosbestic points found in an auxiliary study of three-component solutions with variable Br − :Ni(II) mole ratio. The existence of NiBr + in the form of the [NiBr L 5 ] + pseudooctahedral complex, and that of NiBr − 3 in the form of the [NiBr 3 L ] − pseudotetrahedral complex is inferred, while the nature of NiBr 0 2 remains unclear.