Investigating the high-pressure structural stability of the newly synthesized silicate-carbonate Ca6Si2O7(CO3)2(OH)2.

This proposal aims to explore the high-pressure structural stability of a newly synthesized hydrous silicate-carbonate, Ca6Si2O7(CO3)2(OH)2, formed at 8.5 GPa and 800°C. The novel phase exhibits a unique configuration with hydroxyl groups and trigonal carbon coordination. Using the ID15b beamline at ESRF, we plan to conduct single crystal diffraction experiments under high-pressure conditions to assess its compressibility and identify potential polymorphs or transitions. The results will provide insights into the structural behavior of this mixed volatile-bearing silicate-carbonate and its potential role as a carbon-water storage medium under mantle conditions.