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

Abstract

PETER TAYLOR and VINCENT J. LOPATA. Can. J. Chem. 62, 395 (1984).We have determined equilibrium conditions for each reaction in the solid interconversion sequence PbO = PbloO(OH)6(C03)6 (plumbonacrite) E Pb3(OH)Z(C03)Z (hydrocerussite) = PbC03 (cerussite), in aqueous carbonate solutions near 25°C. Our data yield the following Gibbs energies of formation from the elements, bfG0(298.15 K): plumbonacrite, -53 10 * 3 1 kJ mol-I; hydrocerussite, -1705 * 1 1 kJ mol-I; cerussite, -628.0 ? 3.9 kJ mol-' . Corresponding estimated values of ArG0(373 K) are -5120 2 50, -1643 * 18, and -612 * 9 kJ mol-', 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. [Traduit par le journal]

Some phase relationships between basic bismuth chlorides in aqueous solutions at 25 °C

“…This probably has some bearing on the occurrence of the minerals bismoclite and daubreeite. The narrow stability field of Bi12017C12 is consistent with its apparent absence in nature; similar observations have been made (10,21) on the absence or scarcity of (Bi0)4(0H)2C03 (basobismutite?) and Pb100(OH)6(C03)6 (plumbonacrite).…”

Structure, spectra, and stability of solid bismuth carbonates

“…These experiments followed a strategy similar to that previously used to determine stability limits between lead oxides and carbonates (4). Solids were isolated by filtration, washed with deionized water, air-dried, and identified by X-ray powder diffractometry (XRD), using a Philips PW-1 150 diffractometer with CuKa radiation and a diffracted-beam monochromator.…”

“…The alternative equations involving CO,(g) are more convenient for general discussion of stability relationships, as described in ref. 4, and lead to an alternative expression of the equilibrium constants2 as llp(C0,). Hereafter, p , and p, refer to the equilibrium C 0 2 partial pressures for reactions [ We did not observe (BiO)4(OH)2C0, in a similar series of reactions with "autoclaved" bismutite, probably because it was more crystalline, and hence less reactive, than the "precipitated" material.…”

“…However, we can estimate p , by comparing our results for this system with those for the conversion of PbO to plumbonacrite, Pb100(OH)6(C03)6, reported in ref. 4. The limits for the PbO-plumbonacrite equilibrium (reaction [5])…”

Anodic oxidation of lead in aqueous carbonate solutions. I. Film formation and dissolution at pH = 12

“…'~evision received June 13, 1988. (8), and the stability fields for a number of solids in the Pb0-C02-H20 system have been determined. The infrared and Raman spectra for the various solids have been published (9).…”