Chemical Speciation of Environmentally Significant Metals with Inorganic Ligands Part 2: The Cu2+-OH-, Cl-, CO32-, SO42-, and PO43- systems (IUPAC Technical Report)

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chemical speciation, copper, environmental, ligands, stability con-stants, IUPAC Analytical Chemistry Division

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Complex formation between CuIIand the common environmental lig-ands Cl–, OH–, CO32–, SO42–, and PO43–can have a significant effect on CuIIspe-ciation in natural waters with low concentrations of organic matter. Copper(II)complexes are labile, so the CuIIdistribution amongst these inorganic ligands canbe estimated by numerical modeling if reliable values for the relevant stability(formation) constants are available. This paper provides a critical review of suchconstants and related thermodynamic data. It recommends values of log10βp,q,r°valid at Im= 0 mol kg–1and 25 °C (298.15 K), along with the equations and spe-cific ion interaction coefficients required to calculate log10βp,q,rvalues at higherionic strengths. Some values for reaction enthalpies, ∆rHm, are also reported whereavailable.In weakly acidic fresh water systems, in the absence of organic ligands, CuIIspeciation is dominated by the species Cu2+(aq), with CuSO4(aq) as a minorspecies. In seawater, it is dominated by CuCO3(aq), with Cu(OH)+, Cu2+(aq),CuCl+, Cu(CO3)OH–, Cu(OH)2(aq), and Cu(CO3)22–as minor species. In weaklyacidic saline systems, it is dominated by Cu2+(aq) and CuCl+, with CuSO4(aq) andCuCl2(aq) as minor species.

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Pure and Applied Chemistry, v. 79, issue 5, p. 895-950