High-pressure phase transitions and compressibilities of aragonite-structure carbonates: SrCO3 and BaCO3

Single-crystal elasticity of SrCO3 by Brillouin spectroscopy

“…The very large uncertainties on the values of the linear compressibilities of SrCO 3 are entirely due to the propagation of the uncertainties on c 13 and c 23 . Our results are in qualitative agreement with the linear compressibilities determined by X-ray diffraction in the study of Wang et al [38] and were additionally confirmed by DFT calculations. /GPa is intermediate between aragonite [12] and witherite [38] thus confirming a dependency on the cation radius.…”

“…Our results are in qualitative agreement with the linear compressibilities determined by X-ray diffraction in the study of Wang et al [38] and were additionally confirmed by DFT calculations. /GPa is intermediate between aragonite [12] and witherite [38] thus confirming a dependency on the cation radius. Based on our results on strontianite and assuming a linear relationship between the elastic coefficients and the molar fraction of SrCO 3 in natural aragonite, we extrapolated data for the axial compressibilities as well as the bulk and shear modulus for pure aragonite.…”

“…Our aggregate moduli are shown in Table 2 together with previously published data for SrCO 3 obtained by highpressure X-ray diffraction by Wang et al [38]. The shear modulus G VRH of SrCO 3 has a value of 31(1) GPa which is about 10 % smaller in comparison to that of aragonite (35.8(2) GPa, [12]).…”

Lattice dynamics and elasticity of SrCO3

“…However, details of the elastic behavior of SrCO 3 are also unknown, except for the bulk modulus. This was measured by Martens et al (1982), who obtained a value of B = 58 AE 10 GPa and, more recently, by Wang et al (2015) who gave B = 62 AE 1 GPa.…”

Effect of cationic substitution on the pressure-induced phase transitions in calcium carbonate

“…Unlike CaCO3, the end members SrCO3 and BaCO3 have simple phase diagrams. They crystallize in the orthorhombic aragonite structure up to 22 GPa (SrCO3) and 10 GPa (BaCO3), and transform to post-aragonite with further pressure increase (Wang et al, 2015). The binary CaCO3 -SrCO3 system has been studied at P -T conditions up to 1.6 GPa and 923 K (650 °C) (Carlson, 1980).…”