Decomposition of perovskiteFeTiO3into wüstiteFe1−xTi0.5xOand orthorhombicFeTi3O7at high pressure

The phase relation of ${\text{FeTiO}}_{3}$ was investigated up to a pressure of about 67 GPa by synchrotron x-ray diffraction and analytical transmission electron microscopy. We found that ${\text{FeTiO}}_{3}$ perovskite decomposes into ${\text{Fe}}_{1\ensuremath{-}x}{\text{Ti}}_{0.5x}\text{O}$ w\"ustite and orthorhombic ${\text{FeTi}}_{3}{\text{O}}_{7}$ phases (ideally ${\text{FeTiO}}_{3}\ensuremath{\rightarrow}2/3\text{FeO}+1/3{\text{FeTi}}_{3}{\text{O}}_{7}$) at conditions above 42 GPa and 2000 K. Our study also demonstrates that the phase assemblage of ${\text{Fe}}_{1\ensuremath{-}x}{\text{Ti}}_{0.5x}\text{O}$ and ${\text{FeTi}}_{3}{\text{O}}_{7}$ is the densest of the various systems reported so far for ${\text{FeTiO}}_{3}$.