Magnesioperovskite

Magnesioperovskite refers to the magnesium end-member of the silicate perovskite family, with the chemical formula MgSiO3. It is the magnesium-dominated member of the (Mg,Fe)SiO3 perovskite series and is closely associated with the mineral phase that dominates Earth's lower mantle. In contemporary geology, the natural mineral corresponding to this composition is widely known as bridgmanite, while magnesioperovskite is often used to describe the pure MgSiO3 end-member or laboratory samples.

Crystal structure and composition: Magnesioperovskite adopts a distorted orthorhombic perovskite structure (space group Pbnm) in which magnesium sits on the larger A-site and silicon on the smaller B-site, coordinated by oxygen. The structure accommodates minor substitutions, notably iron, which modifies physical properties and stability.

Stability and occurrence: This phase is stable under the high pressures and temperatures of Earth’s lower mantle, typically above roughly 23 gigapascals. At even higher pressures near the core–mantle boundary, silicate perovskite transforms to the post-perovskite structure, an event that helps explain certain seismic discontinuities. Magnesioperovskite is central to models of mantle composition and dynamics because it represents a major portion of the mineralogy in the deep Earth.

Properties and significance: As a high-density, high-velocity mineral, magnesioperovskite influences seismic wave travel and mantle rheology. Its behavior under extreme conditions informs interpretations of mantle convection, phase transitions, and core–mantle boundary processes. The broader perovskite family, including magnesioperovskite, is extensively studied in high-pressure experiments and diamond anvil cell research to reproduce deep-Earth conditions.