Theoretical upper-bound limitations for mixed-ligand complexes in solution

Abstract

Theoretical considerations allow the calculation of the potential significance of mixed-ligand solution complexes. It can be shown that the solution concentration, [MXY], of a chemical species, MXY, cannot represent more than 50% of a metal's total dissolved concentration, M T . For higher ligand number mixed-ligand complexes it is found that ([MX 2 y]+ [MXY 2)/M T 0.75 and ([MX 3 y] + [MX 2 Y 2 ] + [MXY 3] /M T 0.875. In high average ligand number systems, mixed complexes, MX aY b, can dominate a metal's solution chemistry even when only one single-ligand type species, MX a + b, is important. Mixed-ligand complexes may dominate the chemistry of highly associated hydrothermal solutions.