Phase Diagram and High-Pressure Characteristics of Pyrocarbonates Src2o5

Abstract

SrC2O5 is a newly discovered pyrocarbonate. This study aims to utilize first-principles calculations to investigate its high-pressure characteristics, thereby enhancing the understanding of deep carbon storage and cycle. Following the redrawing of the phase diagram for SrC2O5, it was found that only the P21/c and C2 phases exist under the mantle's temperature and pressure conditions associated with subduction zones, with no evidence of the previously predicted Fdd2 phase. The transition pressure from the P21/c phase to the C2 phase is 35 GPa. The elastic and seismic properties of SrC2O5 indicate that it exhibits significant elastic anisotropy, low density, high seismic wave velocity, and azimuthal anisotropy. Additionally, the thermophysical properties of SrC2O5 reveal a high Debye temperature, good thermal conductivity, a small acoustic Grüneisen constant, and a high melting temperature. These findings provide new insights into the high-pressure behavior of Sr-carbonates.

Keywords: Pyrocarbonate SrC2O5, Phase diagram, Elastic properties, Seismic properties, Thermophysical properties