Stability and solubility relationships between some solids in the system PbO–CO2–H2O

Abstract

We have determined equilibrium conditions for each reaction in the solid interconversion sequence [Formula: see text], in aqueous carbonate solutions near 25 °C. Our data yield the following Gibbs energies of formation from the elements, ΔfG°(298.15 K): plumbonacrite, −5310 ± 31 kJ mol−1; hydrocerussite, −1705 ± 11 kJ mol−1; cerussite, −628.0 ± 3.9 kJ mol−1. Corresponding estimated values of ΔfG°(373 K) are −5120 ± 50, −1643 ± 18, and −612 ± 9 kJ mol−1, respectively. We have demonstrated the existence of a narrow stability field for plumbonacrite, and convenient small-scale preparations of hydrocerussite and plumbonacrite are described. Gibbs energy data for the solids have been combined with selected data for aqueous lead species in a detailed computation of solubility behaviour for this system at 25 °C.