The high-pressure phase transition of strontianite (SrCO3) was investigated at ambient temperature by means of powder and single-crystal X-ray diffraction. The samples were compressed in a diamond anvil cell to a maximum pressure of 49 GPa. Structure refinements confirm the existence of SrCO3 in the low pressure aragonite-type phase Pmcn (62) up to about 26 GPa. Above this pressure, SrCO3 transforms into a high-pressure phase with post-aragonite crystal structure Pmmn (59). Fitting the volume extracted from the compression data to the third-order Birch-Murnaghan equation of state for the low-pressure phase of SrCO3 yields K0 D 62:7.6/ GPa and K00 D 3:2.1/, and for the high-pressure phase this yields K0 D 103.10/ GPa and K0 0 D 2:3.6/. The unit cell parameters change non-uniformly, with the c axis being 4 times more compressible than the a and b axes. Our results unequivocally show the existence of a Pmmn structure in SrCO3 above 26 GPa and provide important structural parameters for this phase.
CITATION STYLE
Biedermann, N., Bykova, E., Morgenroth, W., Efthimiopoulos, I., Mueller, J., Spiekermann, G., … Wilke, M. (2020). Equation of state and high-pressure phase behaviour of SrCO3. European Journal of Mineralogy, 32(6), 575–586. https://doi.org/10.5194/ejm-32-575-2020
Mendeley helps you to discover research relevant for your work.