An international team of researchers has dissected themselves in the journal innovation Discover the presence of oxygen in the solid inner core of the Earth. They claim that in the center of our planet there may be densely packed compounds of iron oxides with atomic composition F28About14.
Searching for the chemical composition of the Earth’s interior is very difficult, because we are unable to take tangible samples from hundreds or thousands of kilometers at a depth. We learn about what the outer and inner core of the Earth can consist of from seismic wave analysis techniques.
The Earth’s core is not just iron. Oxygen may also be present
Scientists from China and the United States, who were studying the question of the possible presence of oxygen in the inner core, conducted a laboratory experiment. They recreated extremely high pressure and temperature conditions. They placed pure iron and iron oxide on both sides of a diamond anvil. They passed a high-energy laser beam through both materials. The compounds began to interact with each other at a pressure of 220-260 GPa and a temperature of 3000 K, that is, in conditions similar to those prevailing in the Earth’s interior at a depth of more than 4000 km.
The new compound created by combining pure iron with iron oxide was something else entirely. It was characterized by a very packed structure. Theoretical calculations of the atomic composition showed that it could be an unusual iron oxide with a high metallicity and formula F28About14.
Could the possible presence of oxygen compounds in the inner core indicate that they are present in other regions of the mantle and core as well? Not necessarily, because the main issue here is high pressure, which is the guarantor of the formation of such highly packed compounds. So far, neither in the Earth’s mantle nor in the Earth’s crust have compounds of iron and oxygen enriched with iron been found – usually oxygen in Fe-O alloys makes up half the atomic mass, so it forms compounds very different from those that would have been generated in the inner core.
It should be noted that oxygen alone cannot be part of the inner core, apart from iron. The effects of sulfur, silicon, carbon and hydrogen have already been demonstrated. Thus, the center of the Earth is not just a ball of iron, but a much more chemically rich region.
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