Simulations Identify New Manganese-Rich Oxide Stable at Pressures Approaching Earth's Core-Mantle Boundary

Computer simulations identified a previously unknown manganese oxide containing four manganese atoms for every oxygen atom that remains stable across a wide pressure range, including conditions equivalent to 2900 kilometres beneath Earth’s surface. 5 million times atmospheric pressure.

The team found several new compounds; the manganese-rich oxide stood out because it stayed stable even though such metal-heavy compositions are rarely stable at everyday pressures.

“We did not necessarily expect such a manganese-rich oxide to be stable over such a wide pressure range. That was the most interesting and unexpected finding,” Shi said. 1103/85kd-vnbt, suggests the compound’s properties could help explain why seismic waves travel unusually slowly through certain regions at the mantle-core boundary.

Shi noted that some manganese-rich patches deep inside Earth may have gone unrecognised in earlier models of how the element moved through the planet. Timothy Lyons at the University of California, Riverside, said the compound could have moved from Earth’s interior to ancient ocean floors, supplying manganese that accumulated in ores around the time of the Great Oxygenation Event roughly 2 billion years ago.

“[It’s] a potentially important piece of the manganese cycle, an element with far reaching importance from the early evolution of life to modern production of steel and batteries and human health,” Lyons said.

Caroline Peacock at the University of Leeds said high pressure can stabilise compounds that would not normally exist near Earth’s surface because atoms bond differently and materials adopt unusual crystal structures and oxidation states under extreme compression.