Thermodynamik und Kristallographie der Minerale der Krautit-Gruppe

Acidic solutions rich in metals and arsenic can accumulate in pore spaces in tailings or contaminated soils. They precipitate arsenate minerals which are different from the usual ferric arsenates with solubility. Such minerals include the arsenates of the krautite group, namely krautite, Mn[AsO3(OH)]·H2O, koritnigite, Zn[AsO3(OH)]·H2O, cobaltkoritnigite, Co[AsO3(OH)]·H2O, and magnesiokoritnigite, Mg[AsO3(OH)]·H2O. In our newest work on thermodynamics of arsenates, we have determined the thermodynamic properties of all these minerals using a combination of calorimetric methods. We have also determined the full crystal structures, including the positions of the H atoms, and shown that minor differences in hydrogen-bonding network lead to different symmetries of these structures. The data can be used to model fate of arsenic at heavily contaminated sites. More information can be found at https://doi.org/10.1180/mgm.2022.140Externer Link