Estimation of Accumulation of Chromium Ion Impurities in the CaSiO₃ and MgSiO₃ Phases of the Earth's Lower Mantle at Pressures of 18–25 GPa

Based on the data of atomic modeling, the different schemes of isomorphic incorporation of Cr³⁺ ions into the crystal structures of CaSiO₃ and MgSiO₃ were tested in the pressure range of 18–25 GPa and at temperatures of 1873–2223 K. Under these PT parameters, the content of Cr³⁺ in these structures was estimated quantitatively. The semi-empirical simulation data are in good agreement with the results of experiments.