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Tetragonal structure of CaSiO 3 perovskite above 20 GPa
Author(s) -
Shim SangHeon,
Jeanloz Raymond,
Duffy Thomas S.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016148
Subject(s) - tetragonal crystal system , octahedron , perovskite (structure) , materials science , crystallography , diffraction , phase (matter) , synchrotron , bulk modulus , distortion (music) , crystal structure , optics , mineralogy , geology , chemistry , physics , composite material , organic chemistry , amplifier , optoelectronics , cmos
High‐resolution synchrotron X‐ray diffraction measurements were performed at 20–46 GPa on CaSiO 3 perovskite (Ca‐pv) synthesized in a laser heated diamond cell. After heating, we observed peak splittings for the cubic 200 and 211 diffraction lines, attributable to a tetragonal distortion of Ca‐pv. The bulk modulus of the tetragonal phase is 255 ± 5 GPa for K 0 T ′ = 4. The observed intensities and d‐spacings of the split lines indicate that the c ‐axis is shorter than the a ‐axes ( c / a = 0.993 − 0.996). This is compatible with either SiO 6 octahedron rotation around the a ‐axes or SiO 6 octahedron distortion (shorter Si‐O bonds along the c ‐axis than the a ‐axes), provided that the observed phase has a tetragonal unit cell. These structural distortions in Ca‐pv can affect its physical properties and capacity for large cations.