Crystal chemistry and compressibility of Fe_0.5Mg_0.5Al_0.5Si_0.5O₃ and FeMg_0.5Si_0.5O₃ silicate perovskites at pressures up to 95 GPa.

ABSTRACT: Silicate perovskite, with the mineral name bridgmanite, is the most abundant mineral in the Earth's lower mantle. We investigated crystal structures and equations of state of two perovskite-type Fe³⁺-rich phases, FeMg_0.5Si_0.5O₃ and Fe_0.5Mg_0.5Al_0.5Si_0.5O₃, at high pressures, employing single-crystal X-ray diffraction and synchrotron Mössbauer spectroscopy. We solved their crystal structures at high pressures and found that the FeMg_0.5Si_0.5O₃ phase adopts a novel monoclinic double-perovskite structure with the space group of P21/n at pressures above 12 GPa, whereas the Fe_0.5Mg_0.5Al_0.5Si_0.5O₃ phase ado

SUBMITTER: Koemets I 

PROVIDER: S-EPMC10587407 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature