Stability of some carbonates at 25 degrees C and one atmosphere total pressure

Abstract

The stabilities of a number of carbonates, both minerals and synthetic compounds, were determined by dissolving them in water saturated with 1 atm. carbon dioxide at 25 degrees C. and 1 atm. total pressure. The pH of the solution was monitored continuously and the equilibrium value determined by extrapolating the pH-time data to infinite time. This equilibrium pH value was used to obtain the standard free energies of formation of the carbonates. The values obtained are listed below and are compared, where data are available, with values listed in U.S. Bureau of Standards Circular 500 or in Latimer's "Oxidation Potentials."