Zur Thermodynamik der Metallcarbonate. 2. Mitteilung [1]. Löslichkeitskonstanten und Freie Bildungsenthalpien von Cu₂(OH)₂CO₃ (Malachit) und Cu₃(OH)₂(CO₃)₂ (Azurit) bei 25°C

Abstract

Abstract The solubilities of Cu 2 (OH) 2 CO 3 (malachite) and Cu 3 (OH) 2 (CO 3 ) 2 (azurite) have been studied at 25° C in solutions of the constant ionic strength 0,2 M consisting primarily of sodium perchlorate. From experimental data the following values for equilibrium constants and Gibbs energies of formation are deduced: Predominance area diagrams for the ternary system Cu 2+ H 2 O‐CO 2( g ) , including CuO, Cu(OH) 2 , Cu 2 (OH) 2 CO 3 , Cu 3 (OH) 2 (CO 3 ) 2 , Cu 2+ and Cu (CO 3 ) 2 2− , are given.