High-pressure X-ray study of LiCrSi2O6 clinopyroxene and the general compressibility trends of Li-clinopyroxenes.
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High-pressure X-ray study of LiCrSi2O6 clinopyroxene and the general compressibility trends of Li-clinopyroxenes. / Periotto, Benedetta; Angel, Ross J.; Nestola, Fabrizio; Balic Zunic, Tonci; Fontana, Cinzia; Pasqual, Daria; Alvaro, Matteo; Redhammer, Günther J.
In: Physics and Chemistry of Minerals, Vol. 40, No. 5, 05.2013, p. 387-399.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - High-pressure X-ray study of LiCrSi2O6 clinopyroxene and the general compressibility trends of Li-clinopyroxenes.
AU - Periotto, Benedetta
AU - Angel, Ross J.
AU - Nestola, Fabrizio
AU - Balic Zunic, Tonci
AU - Fontana, Cinzia
AU - Pasqual, Daria
AU - Alvaro, Matteo
AU - Redhammer, Günther J.
PY - 2013/5
Y1 - 2013/5
N2 - High-pressure single-crystal X-ray diffraction measurements of synthetic LiCrSi2O6 clinopyroxene (with space group P21/c) were performed in a diamond-anvil cell up to 7.970 GPa. No phase transition has been observed within the pressure range investigated, but the elastic behavior at lower pressures (up to 2.5 GPa) is affected by an anomalous softening due to the proximity of the phase transition to the HT-C2/c phase at 330 K and at ambient pressure. A third-order Birch–Murnaghan equation of state fitted to the compression data above 2.5 GPa yields a bulk modulus KT0 = 93(2) GPa and its first derivative K0 = 8.8(6). The structural data measured up to 7.970 GPa confirm that the space group P21/c is maintained throughout the whole pressure range investigated. The atomic parameters, obtained from the integrated diffraction intensities, suggest that the Li coordination polyhedron changes its coordination number from 5 to 6 at 6–7 GPa by means of the approach of the bridging O atom, related to the increased kinking of the B tetrahedral chain. Furthermore, at higher pressures, the structural evolution of LiCrSi2O6 provides evidence in the variation of kinking angles and bond lengths of a potential phase transition above 8 GPa to the HP-C2/c space group. A comparison of the Li-clinopyroxenes (M1 = Cr, Al, Sc, Ga, Mg + Fe) previously investigated and our sample shows that their elastic behavior and structural mechanisms of compression are analogous.
AB - High-pressure single-crystal X-ray diffraction measurements of synthetic LiCrSi2O6 clinopyroxene (with space group P21/c) were performed in a diamond-anvil cell up to 7.970 GPa. No phase transition has been observed within the pressure range investigated, but the elastic behavior at lower pressures (up to 2.5 GPa) is affected by an anomalous softening due to the proximity of the phase transition to the HT-C2/c phase at 330 K and at ambient pressure. A third-order Birch–Murnaghan equation of state fitted to the compression data above 2.5 GPa yields a bulk modulus KT0 = 93(2) GPa and its first derivative K0 = 8.8(6). The structural data measured up to 7.970 GPa confirm that the space group P21/c is maintained throughout the whole pressure range investigated. The atomic parameters, obtained from the integrated diffraction intensities, suggest that the Li coordination polyhedron changes its coordination number from 5 to 6 at 6–7 GPa by means of the approach of the bridging O atom, related to the increased kinking of the B tetrahedral chain. Furthermore, at higher pressures, the structural evolution of LiCrSi2O6 provides evidence in the variation of kinking angles and bond lengths of a potential phase transition above 8 GPa to the HP-C2/c space group. A comparison of the Li-clinopyroxenes (M1 = Cr, Al, Sc, Ga, Mg + Fe) previously investigated and our sample shows that their elastic behavior and structural mechanisms of compression are analogous.
U2 - 10.1007/s00269-013-0569-5
DO - 10.1007/s00269-013-0569-5
M3 - Journal article
VL - 40
SP - 387
EP - 399
JO - Physics and Chemistry of Minerals
JF - Physics and Chemistry of Minerals
SN - 0342-1791
IS - 5
ER -
ID: 49376101