Mixed Halide Complexes of Lead. A Comparison with Theoretical Predictions

Experimentally and theoretically derived formation constants of mixed lead halide complexes are compared at 25.0°C and one molar ionic strength. The formation constant of PbBrCl, β11=79±10, is somewhat larger than the theoretical results, β11=55, predicted using the formation constants of PbBr2 and PbCl2. The molar absorptivity of PbBrCl was observed to be intermediate in character between the molar absorptivities of PbBr2 and PbCl2. Determinations of the formation constants of PbBr2Cl− and PbBrCl2 − are in reasonable agreement with the predictions based on the formation constants of PbBr3 − and PbCl3 −. Mixed ligand species dominated the complexation scheme of Pb(II) in our test media