Data-Mining Ab Initio Study of Gypsum and CaCO3 Modifications at Standard and Extreme Conditions

Abstract

Calcium carbonate and gypsum are very common and widespread minerals widely used in many fields. However, in order to investigate their behavior under extreme conditions of pressure and temperature, a data-mining ab initio approach has been performed. To analyze structural stability and explore different CaCO3 and gypsum phases in these extreme conditions, the most interesting modifications have been submitted to the DFT calculations. Local optimizations have been performed using the CRYSTAL17 solid-state-quantum-chemical program. Total energies of different gypsum phases are presented and it seems that among the calcite phases, the Calcite I (CaCO3 I) phase has the lowest calculated total energy using the three different functionals in agreement with experimental data. Each of the modified phases of these minerals has been discussed and presented in this study. Due to the very wide industrial and technological application of these natural minerals, further investigation could be of great importance, especially their performances in extreme environments.